You can't use a sweeping generality about Toyota necessarily as Hyundai has an overall far worse dealer reputation then Toyota by a large margin from what I have seen. Golf R add on are in the $2,500 to $15,000+ since the transport ship sunk.
The EXACT scenario you posted about the Supra happened with the Veloster N at most Hyundai dealerships. They act like it is an exotic when it is nothing more then a common car finally set up right. Still has the crappy stamped steel control arms, and all the common junky made parts. So you have a car with beefier rods and a tune, better shock valving, and a eLSD and some colored seat bolstering and piping. Don't get near it and you can not drive it or sit in it. Oh we know it is a $34,000 car, most are these days, but they act like it is exotic. So funny when my purchasing dealer ( north of me, he found my 2018 Kona AWD 1.6T in my color , as my close dealer sales sucked with kid salesman that were clueless) the northern dealer said he would never charge a mark up "we don't do that". Yet a year after I pulled my money on the 2WD Kona N I see his dealership was charging a $2,500 dealer markup on the Kona N on Car Gurus, where the 2 other dealers post there with Kona Ns where not. Or at least they did not post it on Car Gurus site. They all suck, forget the car salesman, buy online and get me the car I want fully prepped when I pick it up and I am gone. Then I choose the repair part of the dealership separately from sales. In 4 years I have yet to needed any form of repair or warranty on my car that a dealership or warranty item is needed. I drove through my steering column noise issue, that went away on it's own.
I did like how Bloomington Hyundai's service manager worked with me when I brought up the horrid front to rear brake bias on a stock Kona 1.6T was and we took out multi cars for 2 hours doing brake testing. 80% of the issues went away when I pulled the soft springs out and replaced them with Eibach's. The spring rubber tuning fixed the rest. But I have a good rapport with that service manager. Since you live near me, he is an option for you if needed.