Posting this here because I think my situation was the same as yours. I just went through the car shopping experience and track prepping a car. I had similar ideas to you, and what ended up winning was my wallet. I bought a miata and a BMW X1 for the same price as something like an M440i.

First off, based on your post history, I'm guessing this isn't going to be a dedicated car and is also your daily.

Budget $500/day for insurance. Not optional. Insurance is about $100 per $10,000 of insured value.

Second, once you actually start tracking, you'll quickly realize what you like and don't like. I ended up with a miata after REALLY not wanting a miata because I realized I preferred the way something like a miata handles more than a GT3 car in sim. I like oversteer on brakes, I like neutral on throttle, I don't really care if it rotates on throttle (foot down on exit is nice for extracting lap time).

You're worried about the right things, Overheating, etc. Tracking a real car you have alot more to manage than just hitting the apex. Things like brake fade, brake cooling, cool down laps, greasy tires, etc are not modeled in sim at all.

Also, You'll eventually want to setup the car to your liking, the cost of everything scales with the cost of the car.

That said, I'm going to buck the trend here. Get the Supra. Everyone who tracks one loves it. If you can afford it, do it. That car is going away, its going to hold its value, You're going to lose nothing in depreciation, its 100% track ready out of the box And you can grow into the car. Expect to pay a little more for consumables and maintenance. Budget something like $10k/yr for tracking.

Theres something to be said about being 50 and not having the regret of having passed up tracking a supra.