Ambulance data patch, manual installation.
There are 6 steps to this instruction.

1. Open \mods\update\update.rpf\common\data\levels\gta5\vehicles.meta
2. Search (Ctrl+F for) "ambulance"
3. Replace the entire <Item> entry by the following:

					<Item>
						<!-- Modified by [MRSA Pack] -->
						<!-- If uninstalling the mod manually, head to vehicles.meta outside of your "mods" folder and replace this entire Item with the analogous from it. -->
						<!-- Sorry, no easier way to do it manually here, the whole entry was replaced by our mod. -->
						<modelName>ambulance</modelName>
						<txdName>ambulance</txdName>
						<handlingId>AMBULAN</handlingId>
						<gameName>EMSAMB</gameName>
						<vehicleMakeName>MRSA</vehicleMakeName>
						<expressionDictName>null</expressionDictName>
						<expressionName>null</expressionName>
						<animConvRoofDictName>null</animConvRoofDictName>
						<animConvRoofName>null</animConvRoofName>
						<animConvRoofWindowsAffected/>
						<ptfxAssetName>null</ptfxAssetName>
						<audioNameHash/>
						<layout>LAYOUT_VAN</layout>
						<coverBoundOffsets>RUMPO_COVER_OFFSET_INFO</coverBoundOffsets>
						<explosionInfo>EXPLOSION_INFO_DEFAULT</explosionInfo>
						<scenarioLayout/>
						<cameraName>DEFAULT_FOLLOW_VEHICLE_CAMERA</cameraName>
						<aimCameraName>DEFAULT_THIRD_PERSON_VEHICLE_AIM_CAMERA</aimCameraName>
						<bonnetCameraName>VEHICLE_BONNET_CAMERA_LOW</bonnetCameraName>
						<povCameraName>DEFAULT_POV_CAMERA_LOOKAROUND_MID</povCameraName>
						<FirstPersonDriveByIKOffset x="0.000000" y="-0.040000" z="0.000000"/>
						<FirstPersonDriveByUnarmedIKOffset x="0.000000" y="0.000000" z="0.000000"/>
						<FirstPersonProjectileDriveByIKOffset x="0.000000" y="0.000000" z="0.000000"/>
						<FirstPersonProjectileDriveByPassengerIKOffset x="0.000000" y="0.000000" z="0.000000"/>
						<FirstPersonProjectileDriveByRearLeftIKOffset x="0.095000" y="0.025000" z="-0.075000"/>
						<FirstPersonProjectileDriveByRearRightIKOffset x="0.095000" y="0.025000" z="-0.075000"/>
						<FirstPersonDriveByLeftPassengerIKOffset x="0.000000" y="0.015000" z="-0.080000"/>
						<FirstPersonDriveByRightPassengerIKOffset x="0.000000" y="0.010000" z="-0.086000"/>
						<FirstPersonDriveByRightRearPassengerIKOffset x="0.000000" y="0.015000" z="-0.080000"/>
						<FirstPersonDriveByLeftPassengerUnarmedIKOffset x="0.000000" y="0.000000" z="0.000000"/>
						<FirstPersonDriveByRightPassengerUnarmedIKOffset x="0.000000" y="0.000000" z="0.000000"/>
						<FirstPersonMobilePhoneOffset x="0.155000" y="0.228000" z="0.463000"/>
						<FirstPersonPassengerMobilePhoneOffset x="0.136000" y="0.223000" z="0.425000"/>
						<FirstPersonMobilePhoneSeatIKOffset>
							<Item>
								<Offset x="0.281000" y="0.491000" z="0.536000"/>
								<SeatIndex value="2"/>
							</Item>
							<Item>
								<Offset x="0.156000" y="0.533000" z="0.536000"/>
								<SeatIndex value="3"/>
							</Item>
						</FirstPersonMobilePhoneSeatIKOffset>
						<PovCameraOffset x="0.000000" y="-0.115000" z="0.565000"/>
						<PovCameraVerticalAdjustmentForRollCage value="0.000000"/>
						<PovPassengerCameraOffset x="0.000000" y="0.000000" z="0.070000"/>
						<PovRearPassengerCameraOffset x="0.000000" y="0.000000" z="0.070000"/>
						<vfxInfoName>VFXVEHICLEINFO_CAR_GENERIC</vfxInfoName>
						<shouldUseCinematicViewMode value="true"/>
						<shouldCameraTransitionOnClimbUpDown value="false"/>
						<shouldCameraIgnoreExiting value="false"/>
						<AllowPretendOccupants value="true"/>
						<AllowJoyriding value="false"/>
						<AllowSundayDriving value="false"/>
						<AllowBodyColorMapping value="true"/>
						<wheelScale value="0.2265"/>
						<wheelScaleRear value="0.2270"/>
						<dirtLevelMin value="0.000000"/>
						<dirtLevelMax value="0.920000"/>
						<envEffScaleMin value="0.000000"/>
						<envEffScaleMax value="1.000000"/>
						<envEffScaleMin2 value="0.000000"/>
						<envEffScaleMax2 value="1.000000"/>
						<damageMapScale value="0.70000"/>
						<damageOffsetScale value="0.750000"/>
						<diffuseTint value="0xA2000000"/>
						<steerWheelMult value="1.000000"/>
						<HDTextureDist value="5.000000"/>
						<lodDistances content="float_array">
							10.000000
							30.000000
							70.000000
							140.000000
							500.000000
							500.000000
						</lodDistances>
						<minSeatHeight value="0.946"/>
						<identicalModelSpawnDistance value="20"/>
						<maxNumOfSameColor value="10"/>
						<defaultBodyHealth value="1000.000000"/>
						<pretendOccupantsScale value="0.200000"/>
						<visibleSpawnDistScale value="1.000000"/>
						<trackerPathWidth value="2.000000"/>
						<weaponForceMult value="1.000000"/>
						<frequency value="50"/>
						<swankness>SWANKNESS_1</swankness>
						<maxNum value="10"/>
						<flags>FLAG_IS_VAN FLAG_BIG FLAG_EXTRAS_STRONG FLAG_HAS_LIVERY FLAG_EMERGENCY_SERVICE FLAG_DONT_SPAWN_AS_AMBIENT FLAG_NO_RESPRAY FLAG_USE_FAT_INTERIOR_LIGHT FLAG_HAS_INTERIOR_EXTRAS</flags>
						<type>VEHICLE_TYPE_CAR</type>
						<plateType>VPT_FRONT_AND_BACK_PLATES</plateType>
						<dashboardType>VDT_TRUCK</dashboardType>
						<vehicleClass>VC_EMERGENCY</vehicleClass>
						<wheelType>VWT_OFFROAD</wheelType>
						<trailers/>
						<additionalTrailers/>
						<drivers>
							<Item>
								<driverName>s_m_m_paramedic_01</driverName>
								<npcName>Male Paramedic</npcName>
							</Item>
							<Item>
								<driverName>s_m_m_paramedic_02</driverName>
								<npcName>Male Paramedic</npcName>
							</Item>
						</drivers>
						<extraIncludes/>
						<doorsWithCollisionWhenClosed/>
						<driveableDoors/>
						<bumpersNeedToCollideWithMap value="false"/>
						<needsRopeTexture value="false"/>
						<requiredExtras>EXTRA_1 EXTRA_2</requiredExtras>
						<rewards>
							<Item>REWARD_HEALTH_ENTER_VEHICLE</Item>
							<Item>REWARD_STAT_HEALTH</Item>
						</rewards>
						<cinematicPartCamera>
							<Item>WHEEL_FRONT_RIGHT_CAMERA</Item>
							<Item>WHEEL_FRONT_LEFT_CAMERA</Item>
							<Item>WHEEL_REAR_RIGHT_CAMERA</Item>
							<Item>WHEEL_REAR_LEFT_CAMERA</Item>
						</cinematicPartCamera>
						<NmBraceOverrideSet/>
						<buoyancySphereOffset x="0.000000" y="0.000000" z="0.000000"/>
						<buoyancySphereSizeScale value="1.000000"/>
						<pOverrideRagdollThreshold type="NULL"/>
						<firstPersonDrivebyData>
							<Item>VAN_STOCKADE_FRONT_LEFT</Item>
							<Item>VAN_STOCKADE_FRONT_RIGHT</Item>
							<Item>VAN_BOXVILLE_REAR_LEFT</Item>
							<Item>VAN_BOXVILLE_REAR_RIGHT</Item>
						</firstPersonDrivebyData>
					</Item>

4. Open \mods\update\update.rpf\common\data\handling.meta
5. Search (Ctrl+F for) "AMBULAN"
6. Replace the entire <Item type="CHandlingData"> entry by the following:

					<Item type="CHandlingData">
						<!-- Modified by [MRSA Pack] -->
						<!-- If uninstalling the mod manually, head to handling.meta outside of your "mods" folder and replace this entire Item with the analogous from it. -->
						<!-- Sorry, no easier way to do it manually here, the whole entry was replaced by our mod. -->
						<handlingName>AMBULAN</handlingName>
						<fMass value="4300.000000"/>
						<fInitialDragCoeff value="10.500000"/>
						<fPercentSubmerged value="88.500000"/>
						<vecCentreOfMassOffset x="0.000000" y="-0.650000" z="-0.100000"/>
						<vecInertiaMultiplier x="1.200000" y="1.000000" z="1.300000"/>
						<fDriveBiasFront value="0.000000"/>
						<nInitialDriveGears value="5"/>
						<fInitialDriveForce value="0.180000"/>
						<fDriveInertia value="0.900000"/>
						<fClutchChangeRateScaleUpShift value="1.400000"/>
						<fClutchChangeRateScaleDownShift value="1.420000"/>
						<fInitialDriveMaxFlatVel value="98.0"/>
						<fBrakeForce value="0.500000"/>
						<fBrakeBiasFront value="0.440000"/>
						<fHandBrakeForce value="0.600000"/>
						<fSteeringLock value="37.000000"/>
						<fTractionCurveMax value="1.260000"/>
						<fTractionCurveMin value="1.180000"/>
						<fTractionCurveLateral value="18.000000"/>
						<fTractionSpringDeltaMax value="0.200000"/>
						<fLowSpeedTractionLossMult value="0.220000"/>
						<fCamberStiffnesss value="0.600000"/>
						<fTractionBiasFront value="0.425000"/>
						<fTractionLossMult value="1.000000"/>
						<fSuspensionForce value="1.850000"/>
						<fSuspensionCompDamp value="0.92"/>
						<fSuspensionReboundDamp value="1.16"/>
						<fSuspensionUpperLimit value="0.100000"/>
						<fSuspensionLowerLimit value="-0.120000"/>
						<fSuspensionRaise value="0.030000"/>
						<fSuspensionBiasFront value="0.400000"/>
						<fAntiRollBarForce value="0.080000"/>
						<fAntiRollBarBiasFront value="0.450000"/>
						<fRollCentreHeightFront value="0.530000"/>
						<fRollCentreHeightRear value="0.400000"/>
						<fCollisionDamageMult value="1.000000"/>
						<fWeaponDamageMult value="1.000000"/>
						<fDeformationDamageMult value="0.950000"/>
						<fEngineDamageMult value="1.500000"/>
						<fPetrolTankVolume value="85.000000"/>
						<fOilVolume value="8.000000"/>
						<fSeatOffsetDistX value="0.000000"/>
						<fSeatOffsetDistY value="0.000000"/>
						<fSeatOffsetDistZ value="0.000000"/>
						<nMonetaryValue value="45000"/>
						<strModelFlags>20244049</strModelFlags>
						<strHandlingFlags>0</strHandlingFlags>
						<strDamageFlags>0</strDamageFlags>
						<AIHandling>TRUCK</AIHandling>
						<SubHandlingData>
							<Item type="NULL"/>
							<Item type="NULL"/>
							<Item type="NULL"/>
						</SubHandlingData>
					</Item>