I don't truly know why they left GM any more than you do, but I'd say just as was likely the case with SHR, somebody threw a BIG pile of money at them. There certainly wasn't anything wrong with JGR's (or SHR's) performance levels when they were the "second team" in the Chevy stable. You would have a VERY HARD time convincing me that there was anything either team wasn't getting from Chevy as far as getting results on the track. I think the simple truth in Toyota's case they knew that the original teams they aligned with in Cup were a bunch of dogs, so they wrote a huge check to Preacher Joe to steal away a top notch team that could be their lead team. As time has gone on, they have basically swallowed their lead time and run their whole NASCAR program through JGR. I would say TRD leans on JGR, (if you can still draw a distinction between the two) more than Chevy leans on HMS, because TRD doesn't HAVE anybody else that they can go to.