are the n/a and turbo mk3 supra 5speeds the same diff or are they different

I think it might vary with your option package, not sure. Although i do know how you can check to see what you have without jacking your car up and spinning the wheels. There is a manufacturer's plate on your firewall (in the engine compartment) and on the last line of numbers look at the third set (XXX*XXXX*XXXX*XXXX), this is your axle code. If the last digit of the axle code is a 3 or 5 then you have limited slip differential.

here are all the available ratios, as well as years that they were available.

'92 Supra turbo automatic
Transmission: 4 speed AUTOMATIC
Gear ratios
1st: 2.80:1
2nd: 1.53:1
3rd: 1.00:1
4th: 0.70:1
5th: ???
Final drive ratio: 3.73:1

'89 Supra Turbo 5sp
Transmission: 5 speed MANUAL
Gear ratios
1st: 3.25:1
2nd:1.96:1
3rd: 1.31:1
4th: 1.00:1
5th: 0.75:1
Final drive ratio: 3.73:1

'86.5 Supra NA 5sp
Transmission: 5 speed MANUAL
Gear ratios
1st: 3.29:1
2nd: 1.89:1
3rd: 1.28:1
4th: 1.00:1
5th: 0.78:1
Final drive ratio: 4.30:1

'87 Supra Turbo 5sp
Transmission: 5 speed MANUAL
Gear ratios
1st: 3.25:1
2nd:1.96:1
3rd: 1.31:1
4th: 1.00:1
5th: 0.75:1
Final drive ratio: 3.91:1

89-92 Supra Turbo 5sp (Stock)
Transmission: 5 speed MANUAL
Gear ratios
1st: 3.25:1
2nd:1.96:1
3rd: 1.31:1
4th: 1.00:1
5th: 0.75:1
Final drive ratio: 3.73:1

89-92 Supra Turbo 5sp w/ OS Giken Cross Gear Set
Transmission: 5 speed MANUAL
Gear ratios
1st: 2.701:1
2nd:1.614:1
3rd: 1.215:1
4th: 1.00:1
5th: 0.75:1
Final drive ratio: 3.73:1

All Turbo Supras came stock with LSD's. Sports package N/A's came with LSD's.

All 89-92 turbo's had the same ratios. All 87-88 turbo's had the same ratios. All N/A's had the same ratios.