You are correct, all of the Walkingshaw upgrades are covered under warranty hence why they cost more what trusty old mate Tuna down the road can do.... Also if you put it into perspective, I doubt that the sort of person who walks in to spend $90-95k on a new GTS is going to be too phased about sending $8k on some modifications with full factory warranty, if they wanted more power/performance. .... I am surprised that price does not include some upgraded diff bushes