The factory takes the view that it will invalidate the warranty. Whether they’re legally entitled to take that approach is a different matter but, to avoid any aruments, I went with the factory Stage 1 kit. I have to say I love them. The noise is very loud but, after my first set of Stage 1 pipes failed within a couple of weeks of them being fitted as the weld went on one of them, I really missed the noise when I had the original pipes back put on until a repalcement set of Stage 1 pipes was fitted recently (under warranty). It was so good to get them back. The engine does run quite a bit more freely and, to my (slighly ringing) ears, the sound is great. Don’t underestimate the volume though. The G56 ones are definitely quite a bit quieter (with a more bassy sound).
