[NoDOHC]

You could reuse the GXL gear (it will give you an idea of your speed, just read a little high)

I see two gear part numbers:
1011-17-441A (21 teeth) (hard susp non-turbo only) I read as GTUs
1669-17-441A (20 teeth) (norm susp non-turbo and turbo)

If you think about it, this makes sense, as the 20 teeth would cause the speedometer cable to rotate more per revolution than the 21 teeth would. This is a 5% increase in indicated speed (approximately the same as 4.30 to 4.10 ratio change).

Thus the 20-tooth one goes with the 4:10 ratio and the 21 tooth one goes with the 4:30 ratio.

The difference appears to be in the drive gear sleeve. (one moves the gear further away from the drive gear. Two are listed:
1011-17-442A (hard susp non-turbo only) I read as GTUs.
1669-17-442B (listed for non-turbo and turbo)

The rear housing is the same, as is the gear on the output shaft of the transmission (single part number for non-turbo: 1281-17-341)

I hope this helps!