Nope no limit, it’s like pokemon, gotta catch em all!
You can get to Master is a 60’s Mini, most I talked to didn’t switch cars till after. Just a preference though.
The FFB options are preference as well, I know I had to turn down a lot of stuff at first and then sort of ramp it back up again. At first a lot of stuff I thought was a hinderance turned out to be helpful later on.
Steam workshop has FFB profiles, and also car set ups, good starting point as then you can just make some tweaks here and there to fit your driving style.