They were wonderful to drive at speed but you really had to watch out for the rears. I didn’t find the McLaren too difficult to keep them from spinning up, you just had to be careful on the throttle, but due to the downforce you could get on the power much quicker than road cars. I suspect you couldn’t push them like in real life, though, because of the wheelspin.
It could be that I wasn’t having too many issues because I wasn’t pushing enough, taking longer to get to full throttle, and thus if I tried to reach full throttle as fast as a driver in real life, I would’ve had serious problems with wheelspin.
The Mustang I did have issues with, I was trying to squeeze every tenth I could out of it and the rears just lit up, you had to be really gentle with the throttle.