The brakes in GTR is a good example. The brake pressure and bias settings
are much more in depth than Papy's simplistic braking model and requires
careful setup. It sounds like your wheel is severely holding you back too.
Most other TSW owners have found solutions for game incompatibilities.
Actually, I think TSW have listed a 100% fix on their web site for sims like
RBR.
I'd agree that GP4 is totally lacking in physics and the Ratbag games aren't
that flash either. SCGT is getting far too old now as well. The other sims
you listed though are all top notch if you know what you're doing.
Judging by your fear of Starforce, I'm guessing you're not prepared to step
outside of your comfort zone. I'd highly recommend it though...