the ecm in the truck is a self learning ecm. it will correct for things here and there. the udp won't **** it off. warranty wise, it all depends on the mood of the service manager. TM on the trans isn't a huge issue in terms of holding the truck back. some of it actually works in your favor. i have put some back in it actually. sad thing is, i have spent the better part of 2 months tweaking the trans here and there. trying to get the best of both worlds, so to speak.