Idk I have barley heard of the XTM's.. So I can't imagine what getting parts for them would be like either. I've only heard of good things about the 427. Even 2DMaxLST has been useing them lately for this years race season. And thats after going through like 3 STS 30's. Which we all know are powerhouses.. You guys are gonna have to do a little convincing to get me to like it.