I don't know where you could get upgraded gears and synchros for the tranny, but that would be pretty important, too, provided you were putting down enough power for it to matter. I think the best way to approach the tranny issue is to find some car that a similar style tranny can be sourced from. IE, side mounted, same bolt pattern as the stock G15 transmission, with similar bolts/studs for the flywheel and similar surface area to allow for the clutch to work. Also, the hydraulic systems would need to be comparable. If anyone out there has any info on ideas for the G15, or possibly a different tranny all together (6 speeds! Whoo!), it'd be verily appreciated if you could post it here. =)