Now is definitely time to do it before the radiator gets installed. So much for being the fastest 5.3L truck, huh. If you have the money to do it, git-r-dun! Now that the install has slowed down from our earlier feverous pace you can start thinking about doing the turbo and just bypass the NA mode. Just think, you'll only be out the funds one time instead of twice going NA then boosted. DO TURBO! I'd like to turbo mine some day in the future but that will be in a few years.