Warranty issues on 1965 'Stang door handles and the quality of the GT fog light kit are two I remember. Personally, I think this owner might just be the hard to satisfy type. But one other said steer clear. I'm gonna use you. But, I give everyone one chance and stick with the best. I happen to have Metro Musclecar (formerly Metro Mustang) about a 30 minute drive away from me. From them, suspension, steering and brakes.
There's no telling, but I think it's pretty well known that our level of "discretion" when it comes to returns and warranties is high.. And you just can't imagine some of the unreasonable and sometimes batty claims we have to field and negotiate our way through in the process of satisfying customers..
Some customers return 70-80% of everything they buy, like clockwork... And if they did business elsewhere, they'd have the same exact grievances, never satisfied, perpetually disappointed, muttering "crap, junk, crap, junk" between every 3rd word they utter.
The "steer clear" guy, that totally confounds me. But I won't lie, there's been rare occassions that either myself, or by my consent, certain customers have been (deservedly) told to go pound sand... And who knows what those folks may say at car shows and cruise ins.. You can't do much about that, you have to rely upon your overall reputation to defend against that.
We can't please 100% of the population 100% of the time, which is why there's a vast array of suppliers and choices out there.