I would go for Dynomax or Magnaflow they sound much , much better then Flowmaster IMO
Flowmaster mufflers sound nice at idle but as soon as you hit the gas it rattles like an old loose tin can
Anyhow going cheap on mufflers i would rather go with Thrush then Flowmaster any day
The one i would buy would be Magnaflow single in dual out
http://www.magnaflow.com/02product/02muffler.asp
Go check a few video on Youtube for the 3400 engine sound with different mufflers & make your own mind about it & you'll probably see/hear that Flowmaster are not so great after all...