Eradium

I don't know what could be done  with a stock meta - the advantages of the modded meta are too great for me to consider returning back to it. Here is a list of the cars which I have found work well with their respective modded cars:
 
Crown Victoria - STANIER (police also works but Stanier feels more like a Vic)
Taurus - FQ2
Explorer - GRESLEY
Charger - This one is weird. Two different 2015 models behave entirely different from eachother - POLICESCO's work well with FBI while Bugs' doesn't. POLICE2 works well with some models - BUFFALO and BUFFALO2 also work sort of well but all seem to have a form of the inverse tracking issue, especially pronounced on 2014 models. Experimentation is needed here
Tahoe - BALLER, BALLER2, GRESLEY - Tahoes have issues with rear-end-squat and easy spin-out that is more pronounced with certain handling lines. Experiment with large SUV lines to find one that works the best
 
This pretty much covers everything - if there are new vehicles or ones that don't work well, finding the vanilla equivalent and using its handling line in the vehicles.meta entry (as long as it has the same number of doors) will work well.
 

I am running a huge car pack I found on gta5-mods.com and it appears that the game is not only stable but runs at nearly the same FPS as when the game was stock! The engine is much better this time around. Go for it! I'm running an i7-4790k, GTX 580 1.5GB. Solid and stable at 60-80 FPS. When you get into super high load stuff, which would drop the stock game to 50, it still dips to around 50-45 FPS. I remember IV used to tank to below 20 with laughable reliability; I have only crashed a couple of times in the last two weeks. 

That is absolutely gorgeous. Incredible work!