I had a play around with this last night and thought it would make a good RC car, wasn't going to put it onhere but when I realised how easy it was to make I thought maybe other people would want to have a go at making it as well.
All the cars other functions are not effected.
Medium motor to steer
This three holed grey beam is essential, It stops the gears from slipping.
Plenty of room to add lots of different gear ratios.
Remove the Lego V8 engine. Add an XL motor, if fitted correctly as per the picture the bonnet closes fine.
The blue connecting part to the left is all that's needed to hold the XL motor to the car chassis.