Just additional input: Read up on comments on MBRP 5316409 and also viewed the install over You Tube. If you live in salty area, your first concern is potential corrosion. The material of construction is paramount. That said, 300 series (304 SS) versus 400 series (409 SS) is preferred. 304SS has higher nickel and chromium content while 409SS has much less. 409SS is a harder material due to the higher carbon content but more susceptible to corrosion. 304SS is non-magnetic while 409SS sticks to a magnet. Easy to tell between 304 and 409. Viewing the You Tube install of MBRP, there is difficulty in the fitment or geometry at install due to its construction (butt connection of tubes together). Probably requires more than one person to do install or fitment squarely.I believe the 1320 system will outlast the life of your Tundra. Specially the existing exhaust header to cat will corrode and fail first due to cyclic loading and corrosion overtime. Even 304 will corrode overtime for the same cyclic loading and environmental conditions. 304SS is not immune to corrosion, but can retard potential corrosion. When I removed the stock exhaust, I already have corrosion from the existing catalytic carbon steel flanges. I live in South Florida and my Tundra is 5 years old. Overtime, because of dissimilar metals, there would be galvanic corrosion introduced. Salt laden environment is just harsh and need regular maintenance or flushing of salt crystals.
Above said, the guarantee concern is not significant. The cost of 1320 versus TRD Pro highly favors 1320. Just an added information, I luv the sound of 1320 which is probably similar to TRD Pro. Again, 1320 exhaust is Sweet!
Compared to 1320 with flange connections which make install a breeze and easily completed by one person. I believe the flange connections are superior than the flared tube butt connections, specially during maintenance or dis-assembly.
Sound wise, these exhaust systems are probably similar with mellow deep sounding and not annoying.
Price wise, all are competitive, excluding TRD Pro, Borla, Magnaflow, Corsa, etc... which is hitting $1K and higher.
Lifetime Guarantee: Is a factor and I wonder why 1320 due to its material construction and workmanship only provides 1 year? But as I mentioned earlier, it is not a concern to me primarily due its construction and easy install. The You Tube install of TRD Pro utilizes bungee cords in the installation process....thumbs up!