the lowering problem can be overcome by using xr4x4 front shafts which are marginally longer and dont pop out.
Gearbox, easily obtainable forma 2.0 dohc xr4x4 (all you do is change clutch fork and pin) and its the same box without the cossie price tag, plus its only ever been run on a 2.0 shitbox with fuckall power so should be in good nick
The diffs etc... should be ok for stage 3 power but if not the xr4x4 ones again fit straight on and are same as cossie but shorter ratio I think so more acceleration (probably a good thing if its a track car)...if front diff cacks itself get a steel sandwich plate from somewhere like R&B
Stripping it out helps make it go better too
Dan