[wassy4]

I've taken my car in with a full straight pipe exhaust from turbo back. Never had any warranty issues, just comments about how loud the start up is or how good it sounds. It's good to build a relationship with your service advisor and make sure they are ok with it, but most of the time they do not care about mods if they aren't related to work they're performing. If your turbo fails and you have a catless downpipe, they might try to blame the downpipe for the failure just cause it's directly attached to the turbo.