To someone who doesn't read japanese, it's really weird.
It's actually called "Super Cowled Mini 4WD Super Factory" or something similar, and the GunBuster XTO part refers to the model car body that comes with the game. I think it fits some generic model RC chassis from Tamiya.
As far as I can tell (and I haven't looked that hard at it), all you do is tweak the set up of your car and maybe buy new parts for it because, as far as I can tell, all the racing involves is letting the car go and waiting for the 'race' to finish.
I might have to try to look at it again, but there's only so many times you can beat your head against a brick wall...