Has anyone ever heard of thse mufflers? I called my local meineke and I was going after the flowmaster 40 series for my gp gt but he said they sound good and loud on the grand prix's but they can sound bad athigh rpm's i guess (not a strong sound i guess) but he said the vortecs are really good sounding and they have more low than the flowmaster 40 series.

Affordability, i would go with the Dynamax mufflers. My buddy has them on his gp and i luv it. i have cats and resonator only and luv the sound. its a little loud. but hey flowmaster from what i have heard sounds a lil louder than factory with a 'sissy' sound. i would consider looking at teh the dynamax and the SLP exhaust.