The 40 series resonate in the interior, the 50 do too but not as bad. A straight through design like the magnaflow or even the aero turbine will not resonate as bad. With a specifically engineered design like the Corsa you will have no resonating inside the car. I thought a lot about changing out my exaust but have decieded to just stick with the stock mufflers in a car like the V. I don't want it sounding like a 60's muscle car anyhow.