The stock turbo is pretty much maxed on E30 all else being stock. You can see some decent torque gains with additional mods to the intake, but HP will stay stubbornly low.
The turbo is THE limiting factor on this car in my opinion. My plan is to leave most things stock and upgrade to an S280. I'd like to see how much power I can make for as little money as possible. Accessport, S280 with an 93 and E30 tune.