TLIXX
I'm using SVN 274 (used 269) before. I tested many races with ZeroGS and didn't find races with problems. But I didn't manage to start any race with GSdx

. Maybe that's game version related??? I have NTSC - 517.19.
Gabest
As for Shadow of the colossus. The CPU loading is always 99% for me. Most of the time I get 10fps in-game (anyway I didn't get far from beginning

so maybe things are worse in other places). BTW, glitchy graphics is a broken blur??