I currently have a 2.5 inch DP & exhaust, but my magnaflow is only 2.0 inside diameter, will that little drop in diameter hurt perfromace much?

Car made numbers in sig with above exhaust, but next year hope to make around 300whp. Should I go 3 inch and bigger diameter muffler? Or just stay put.

Thanks

 

ya, its definitely restriction. Why not open it all the way out to 2.5 all the way.