my 32a gearbox has 1st-5th PAR straight-cuts (synchro) and a Nismo 1.5 mech LSD.
I'm hoping to work out the gear ratios and final drive.

The website says custom ratios are available: http://www.par-engineering.pl/index....=article&id=48
After plugging some figures into a calculator, the closest figures (from my driving experience) are listed here on PGA: http://www.users.on.net/~paullus/pul...arboxinfo.html
PAR straight cut gearset:
1st 3.1
2nd 1.93
3rd 1.28
4th 0.956
5th 0.810
Final 4.167:1
Where did these figures come from? is it most commonly recommended by PAR, even though it differs from the PAR website?

But my 5th gear is long as fark.
The previous owner once said it was longer than N14 5th gear, and ive done 220-240 (speedo accuracy, is there such a thing?) in 5th gear at no more than 5,500 rpm. Even with lots of power its just doesnt gain much speed in 5th.

what would the likelyhood of the final drive being changed when the gearset or LSD were fitted?

nameplate 4.1: