i have a 2008 mazda 3 2.3L and i just purchased a universal magnaflow muffler and wanted to knw if i should keep the resinators or just run a striaght pipe from the cat to the muffler?

I want i nice sound but dont want to loose any HP while doin it.

 

im sure the after market exhausts will add horsepower.

I'm also thing about getting either magnaflow or borla for my '11 m3 2.0.