the trd exhaust comes with a 1 year warrantte against defects no matter who installs it but if toyota installs it it will be covered by teh factory exhaust warrantee for how ever long that is
I think it's like 60,000 miles on the toyota warranty. The exhaust wrrany is for manuafacturing defects, but not corrosion or anything else. if a weld breaks on it's own (no rust/road hazard damage, they'll fix it in the first year, that's about it.
If the dealership installs it, it's covered under the car's warranty, if in 60,000 miles it rusts, breaks, falls off, whatever, you'll get it replaced for free (as in a new TRD
exhaust). no matter what happens, the exhaust will be fixed or replaced at no cost. It's worth the $60 or so to have the dealer do the install. better than paying another $500 on an exhaust if it breaks after it's first year of use.