To install this, simply drag and drop Buz2 to your resources folder.  

Feel free to rename it

Go into your server.cfg (or resources.cfg if it's there) and start or ensure the name of the folder (CaSe SeNsitIVe!)

by default you should have either:
start Frog2
or 
ensure Frog2

Once done start your server and voila! Enjoy a realistic handling'ed helicopter! :)

WARNING: Within fivem, there are many scenarios (events) that involve the AI (aka computer) pilot flying near you when you drive / head to particluar locations.  Because the AI ped is used to the basic ass handling, the pilot in the game (with the new handling) will go crazy, bobbing, and weaving back and forth, and will eventually crash :( - Please know that this is the sacrifice for realistic handling.  If you're not a fan of this, you can revert back, or find a way to get rid of the frogger scenarios.  

The following locations where I've seen this occur are:
Los Santos Airport
Vesspicci  helipad 
Downtown los santos
Vinewood hills

RIP to ai pilots who couldn't control the beast!