The codemasters game Race&Driver I found awful as the controls vs reaction of the cars was wonky and GRID uses the same setup so it probably is hosed too.
Mario Kart just is what it is and handles fine, but forget finding a fair and fun online battle, and 150ccs is for sadists who like stupid cheap ai.
Speed Racer I've barely scratched using an emulator but it handled better than anything I've used on a real DS, though Asphalt Urban GT2 is pretty damn spectacular too but it's only fault is being easy to where I just won't want to re-play it a 2nd time after I unlocked it all and sold it (rebought and never bothered much.)
I'd avoid the original Asphalt Urban as that was just awful with some badly handled turning/drift mechanics and some questionable(very) hit detection in some cases being nearly twice the width of the visual(like a truck that had 50% more collision vs visual size to each side.)
Those all are what I have bought/tried out, and I'm not very well up on whatever else is out there as far as American releases go but I really do need a good racer too and likely when I got the cash will just get a legit copy of Speed Racer.