I can really sympathise with that view, Allon - my pc is bulging with every kind of download for GPL, SCGT and GP3!
If you haven't actually put the openGL file into your GPL folder you will certainly be running on D3D. My game seems to run fractionally more smoothly on OpenGL, the only real difference being a degradation in the quality of the view in the mirrors - but then I don't use them much anyway!
I've just decided to leap out of my beloved Ferrari and get back used to the Ltus again. Within 10 laps of Monza I was a second quicker than in the Ferrari.
Have you set a rank for yourself ar GPLRank yet? As I haven't set times on all the tracks yet, I can't get a rank myself - but I'm working on it!