I've yet to be in a GT3 season, I like the idea of a mixed make series. I struggle with understeer in any car, as much as I like the supercars for a season I'm finding they steer like a dog for me. My setups need work to compensate for what the joystick lacks, but that can only go so far.
For the supercars the 2 McLarens have the same specs, why not put them both in? Is there something I am missing in difference between them other than the 650 looks better.