I own the borla system and I love it. It is not too loud, but if you give it some gas you will know it is there. As for the flowmasters, the 50 series would be a better choice if you are looking for a mellower tone. As far as stainless steel mufflers go, flowmaster now makes them, but not sure if they make it for the tundra yet. As stated previously, I would stay away from the TRD setup. Borla or flowmaster, I don't think you will be disappointed with any of those mufflers. Aloha