I don't think JC had an ulterior motive by getting rid of the GT. I would be pretty damn pissed if I just paid $150K for a car and the damn alarm started going off all the time, Yes, its an aftermarket alarm and all that stuff, and he could have taken it off blah blah, but that's how the car came. If something breaks, you normally take it to the dealer, and you'd expect that to fix the problem, especially considering this is not a cheap car. Why should he have to take the alarm off, even if its useless, it should be the dealer's responsibility to get the car working!
I might not go as far as he did, but I would still be damn pissed and certainly never buy another Ford product.
As to the F430 - I'm pretty sure that's just the usual JC way of saying "I like this car"; he tends to exaggerate things.