Both of these kits are very, very easy to install, completely bolt on, no mods required, no welding at all.
IdParts kit time to install
20 minutes for a Pro, 30-45 minutes for a first time installer
Kerma kit will probably take 2-3 hours to install for a first timer, but it is the entire exhaust, sans a muffler.
Kerma TDI exhaust