Thanks roosterreagan, I can confirm that I'm running both f104 FOAM tyres and wheels. I had a play today with some shims on the front suspension. I was planning on lifting the whole front suspension section, but realised I couldn't due to the length of the screws. So at best I added about 0.5mm. I also moved the positions of the shims on the kingpins, which gave me a few extra mm. But it still sits at 5mm not the 4mm I'm chasing.
Also it was 1998 when the FIA introduced the 1.8m wide cars as well as the stupid grooved tyres (3 at the front, 4 at the rear).
I can't get the rear wheels to match the 200mm width of the front end... Not without a sizable bush on the inside of the wheel. Leaving a very small amount of thread available for the wheel nut!
Would pics help to explain my issues?
Side note... How's the sf3?