I just tried to edit part of the OG Xbox emulator on the 360 to make Crazy Taxi 3 not lag, found a cool graphical glitch on xefu1_1.xex and xefu2.xex. All the glossy metal surfaces (fare meter, gear, ready-set-go text etc) appear as a flat grey color. Left image is emu.
it was fun learning how xefu has an inital "xbox.xex" that checks the game against a list to see if its playable, allowed to go on xbox live, what emu etc. had to overwrite some random NFL game to put Crazy Taxi on the list