The speed difference is most noticable in the vertical force (bumps, curbs etc.).
The wiper motors sometimes had troubles with these fast repeating movements, I had to increase the values for vertical force to compensate for this which resulted in an increasing error, but a better feel.
For the rest the speed is coherrent to the actual game values, a car doesn't tip over instantly when taking a corner, neither does the sim, so for these movements the speed difference won't be very noticable because the software regulates the speed.
On the video I'm still using the increased values, that's why the bumps look more like waves instead of actual bumps.
All in all like motiondave mentions: I've got a lot of tweaking to do, this was just a first test.
A few friends of mine drive racecars (jeroentje.nl tuning team)and one of them is very good with everything that has to do with electronics as well so he will help me to get everything as realistic as possible.