Yes you can use them. Like George said it's really too small so don't expect good results. Also like you mentioned it might not be worth your trouble to modify your maifold or the turbo to make it fit. I'd say just try and find a decent used T25/T28 from a BB/GTi-R if you want a nice mild boost. That way you just slap it on the stock nissan SR20 turbo maifold.