Auto-upgrade will let you tailor a car for peak performance within a class... it's fairly intelligent at suggesting parts. I've noticed it tends to weigh certain parts over others, and it's not afraid to downgrade installed parts to get as close to the class PI cap as possible -- including body kits, which I find particularly annoying. I usually just manual upgrade anyway. The new shop is
fantastic. You always keep any parts that were previously installed, including factory parts. You can sell "old" upgrades if you want (at a loss), but you can't sell factory parts. I'm a packrat -- you never know when you might want to downgrade that S-class to squeeze it into an A-class race.
What am I missing with this 8th place start bullshit? Even when my car is 100+ PI ahead of the next fastest car, I start last? That makes no sense, especially when the rest of the starting grid is organized by PI! WTF! There's no heat event or anything.