Hi Roland,
the red & white Compact Porsches are from the "Takeover-Set" ,
with diode and capacitor you can run with both cars on one lane.
Just remove "this crap" and they will run on a normally analog track.
For the tires maybe Peter can tell something about the "CarGo Tires",
heard that they were also produced for Compact Porsche ?! ...
Greetings
Michael