I have the flowmaster 50 series delta and I think it sounds real good. It is more throaty and not ricey but keep in mind that you have a V6 so it wont sound like a V10. I think it is just loud enough but not obnoxious. I would put it on again and possibly go to a 40 series.
I am thinking about trying to reduce all the wasted space under my bed, and with the stock muffler still on there…there is a lot of space wasted!
I have been considering the new Flow master extreme off road muffler, but I do not know anyone else that has tried it yet. But I think it has a very good concept going for it! Should be ultra strong to bang against things under the truck in the rocks!
Go with the 40 series FM. I have mine dual out and it sounds nice. VERY NICE!! I have it 2 1/4 in and 2 1/2 out. You do get a bit more MPG and some power, but I think its worth it. I get a lot of compliments from other truck owners.
Anything is almost better flowing than the stock exhaust. I wouldn't waste time replacing your cats until it is clogged. Save the cash and buy the TRD or Edelbrock headers and a good cat back system. Or depending where you live, get a test pipe to replace the cat.