Wait, the R came with 5P's? That's not terrible, much better than what they throw at us plebeians. I do wish they'd just have a Michelin 4S option, but ultimately, it's just a quick trip to Discount Tire anyway.
Yep, the R came with 5 Ps. The side walls rolled easily and the edges of the tread were chewed up fairly easily as well. They were quieter than the Michelin's, but not as well rounded of a tire. I've got the 4S installed now and they are great other than noise when turning the wheel at slow speeds. I get some humming. I also had the EC Sports, they were SUPER quiet and comfortable, but forget any kind of aggressive driving on those. The side walls rolled so easily I'm surprised the edges of my wheels weren't touching the ground. Though, I did have them in a 19" which could have been the cause. I'm sure they would be better in an 18" instead.
Back to the topic at hand. I agree with everyone else here that the used car market is way too crazy to even think about buying a car. The only strategy in this market right now would be to trade in / sell something used to come up on some cash and then by a new car. I'd be worried about buying a modified R in the first place, regardless of the parts that are installed. I don't trust people doing the little things right. Broken clips, exposed wires, improper torqueing, reusing one time parts like stretch bolts. Now compound that with the current market. You're just asking for trouble.
I also don't think the MK8 is going to bring prices down on the MK7s & 7.5s that quickly either. Supply chain issues, semi conductor & chip shortages, prices of fuel and other related business overhead costs. It doesn't seem to be slowing down at all. Prices may take a slight hit because the newest model comes out, but most people aren't in the position to spend 45k+ on a car right now either. Not to mention if dealerships do decide to mark these things up, we could be looking at 50k before TTL. EVs also cost too much for most people, so expanding that market is going to be very difficult until those prices start to come down. We will see what happens when Tesla releases their EV for 25k. It's going to dominate the market.