So I just did some tests for myself. Prior to this I wasn't completely upset but also not WOW'd. Im running VRC on a good gaming PC (Can play COD and such on max settings). Anti-aliasing and anisotropic filter don't seem to hurt FPS as much as the smoke setting does. Turning smoke on and off is like using two different games\cars\system. My FPS will hold strong at almost 300, turn on smoke and it drops 100-150 and the car feels stupid again. Regardless, turning all these settings to off seems to be the best and while everything doesnt looks as cool, it sure works better.
normally I dont worry about FPS because anything above 60 in theory doesnt matter. Large fluctuation in it can hurt though, in this case it seems to really show.
Having a blast with VRC now while there is snow outside my window, whos up for some racing!