[Scuderia_Turini]

I think there are two types of guide. One has a peg (approx 2mm) at the front end of the "tiller". Other has a small blade at the front and a sperate one a few mm back.
Will PM a couple of photos from the most recent collectors guide.

For the car above, I replaced the front axle with a standard metal one simply glued in place. So fixing the new wheels was no challenge. They are the five-spoke star type wheels from the 90's Scalextric cars. Replacing the front wheels on the standard axle unit would be fiddly and at the end of the day, these guide units were always too floppy for serious use. 

The gears become brittle with age so its good that yours work - also that the motor brushes are working. The magnet is probably past its best though.
Too much rear grip might worry the gears...