I had my stock SVT exhaust with only the resonator replaced with a glasspack on my car for about a year and a half. The tone was perfect in my opinion (almost exactly the same as the Borla I have now, before I gutted the cats), and never hollowed out. The glasspack I had was from Autozone, and was the offset one.
I can't compare it to the magnaflow as far as sound because I have never heard one, but the price was definitely right! I still have my stock exhaust in my garage with the glasspack still attached.
