Yes. The MagnaFlow is much louder than the stock exhaust on a 01 GT and you can diffenantly hear it when you give it some gas. However, it is a little metallic.
I went with the MagnFlow mufflers, straight through verses the chambered, because I did not want a lot of droning while I was cruising. With a convertible this would get alittle annoying for a daily driver. There is some droning however, it is a tolerable level. I would imagine with the three chambered MagnaFlow (I think they are called MagnaPaks) mufflers you would get a deeper rumble and much more noticeable sound.
The main reason I went with the MagnaFlow full stainless steel exhaust (cats and X-Pipe) verse the Bassani was the price difference. I think you are paying more for the Bassani name brand than anything else however, I could be wrong.
BTW. I added 23 rwhp with the MagnaFlows.