nopsi I did something similar... removed both stock muffler and resonator and added a 2.5" dia. magnaflow... but I got the 24" or 28" or whatever the big one is, fearing it'd be too loud without TWO mufflers.
So now it does sound quite nice at WOT, and at just above idle it has a nice grumble, but at around 1400-1800 i have crazy bad resonance to the point that between 50-60mph cruising I find myself downshifting to 5th, even maintaining constant speed on flat roads is a nuisance, never mind very gentle acceleration. I think if I went with an appropriately sized muffler I would have been better off...
ahh live an learn. I'm just going to get my original exhaust setup welded back together so i have the stocker intact and normal, and go with the borla. My friend did all the work (tig welded mandrel bent pipes the works) so it only ran me $230 for the muffler shipped to Canada.