Broke Rear Diff on Evo5GSR can Lancer GSR Cm5a rear diff work?
 

I have a 98 evolution V GSR model with ayc. Rear diff is damaged and a used e5 diff costs $2500 in my country. I have a rear diff LSD from a 97 Lancer GSR 1800cc CM5a model readily available to me for free. Can this work? Also the previous owner has changed the final drive in my GSR gear box to the RS final drive 4.529 to 4.875.

GSR CM5A gear ratio
MPH
1st gear ratio 3.583
2nd gear ratio 2.105
3rd gear ratio 1.407
4th fear ratio 1.031
5th gear ratio 0.761
Rear gear ratio 3.416 (not sure but found this online)MPH154@7000 160@7500
Top gear ratio 0.76
Final drive ratio 4.11

Evo 5 GSR gear ratios Standard
1st 2.785
2nd 1.950
3rd 1.407
4th 1.031
5th 0.761
rear diff: 3.307 (not sure but found this online)
Final Drive: 4.529

My car has approximately 380-400whp and I do drag race it and launch it very hard

This is a pretty specific/technical question, especially considering we didnt get either model you are talking about in the US. You might have better luck contacting one of the drive train vendors on this site directly with this one.