Thanks for all the input. Our uses Scalextric Sport track in digital format. We have a class called Vintage Sports which allows GT and sports cars from the '60s and '70s, no modifications allowed, except for the fitting of Slot.it 21,500 rpm motors in cars which have much slower motors, such as the Scaley GT40 which comes with an 18,000 rpm motor. The Slot.it GT40 , which comes standard with their 21,500 rpm motor, cannot therefore be modified. I note that the MRRC Porsche 910 comes with a 21,000 rpm'slim can' motor and looking at the photos of this car which make it appear quite small, the power/weight ratio should be favourable. Photos of the Sebring chassis fitted to this car also suggest that it is fitted with 2 magnets which should make the handling okay. I know that the Slot.it GT40 has far more potential if one is looking at further modifications but , in this class, no modifications are allowed. For the record, a variety of cars are raced in this class at present, from the previously mentioned GT40s from Slot.it and Scalextric, to several models of Revell-Monogram cars and others.
Steve