You will definitely get gains, but on an N/A car, it won't be crazy amounts. A tune would get you more even if you keep everything as stock. My V36 has a custom system. FI HFC to 2.5" mild steel to a magnaflow xpipe and 2.5" all the way to HKS Legamax mufflers. Sounds good, no drone, but I doubt it made more than 5hp lol.