I have the Bassani mufflers too and agree with your assessment. I've found that there is some exhaust system resonance or drone when climbing steep hills or in the mountains, but can either shift up the rpm range or the climb is soon over. Most of the droning complaints are from those with autos, whose only recourse is to increase the throttle.
They definitely make the car sound a lot more sporty, and sound down right impressive at WOT.
I've received many complements since the install, I'm sure you will too. Good luck.
Edit: I had mine installed at Midas, it took about an hour and $100. Sent from AutoGuide.com Free App