Be careful with the exhaust. I'm sure you know all too well how horrible civics can sound with cheap exhaust. Keep it respectable and not too loud. The biggest performance gain would be through a turbo system. But with FWD, you're going to end up with huge torque steer and traction problems. They're also very sensitive systems, you can absolutely demolish your engine with a turbo if you don't know what you're doing. If you consider going down this route, buy the book "Maximum Boost" by Corky Bell, it'll really help you out.