Sad but true. For a circuit car above... probably B class, you want the Forza aero. Below that the bling kits can be useful, but once you get to some high speed cornering, you really need proper race equipment. Especially if you're a high-downforce driver as you said (I am too). What sucks is that some cars can't fit it for whatever reason. I didn't seem to be able to equip the race aero onto a Pontiac Trans Am.