I have a 2006 GT with a K&N cold air intake. I'd like to change the exhaust for better sound & performance and was looking at a Flowmaster cat back system with the American Thunder Mufflers. Can anyone tell me if this is a good choice for this car?
Not real fond of Flows myself. Flowmaster mufflers are notorious for a part throttle drone. Every car I've ridden in that had Flows had that drone and it doesn't take long at all to really get on my nerves. To be completely honest, I've never ridden in an S197 with the American Thunder system, so I can't say for a fact that system has the same drone, but based on past experience I'll never consider any Flow system for any of my cars.
Considering your car is nearly stock, you really don't need a cat back system. The oem pipes are more than adequate for the 300+ hp of these cars so an axle back system (basically just the mufflers and tips) is all you really need and you can make a big difference in the sound with the right mufflers. I'd check out magnaflow mufflers, or go for FRPP FR500S mufflers. You could also try finding some GT500 take offs for a sublte increase in tone and volume over stock GT mufflers, but they are too pricey to buy new IMO.
Actually the OEM GT500 axlebacks are the same axlebacks that come standard on automatic mustang gt. Like Rick said, you only need axlebacks. A few suggestions would be: look for a used set on this or other mustang fourms. Craigslist also works. Join a local mustang club in your area and listen to other 05-10 mustangs. I am sure they will also be able to help you out.
I installed Flomasters American Thunder axle back system last month. Got em off ebay for $125 shipped! They sound good. And as far as loudness goes, they are somewhere inbetween stock and slightly piss the neighbors off when the car idles next to their house! Not super loud I guess is what im trying to say.
As far as drone goes, I only notice it on the freeway, and its really not that bad. Overall im satisfied.
However if you plan on ditching your cats, from what Ive read these mufflers are real raspy without converters. Just what Ive read though.
I would say if you hear a Mustang driving by that sounds good to you ask the owner what he has. I have mufflers off of a Bullitt which are quiet at idle but noticeable when you're on the throttle. I just installed American Racing headers and they do not drone at all.
I think pypes mid muffler or FRPP stingers sound the best on the S197. I have also listened to a few with flowmasters new super 44s and they also sound great on the s197.