WHEELS AND TYRES
To an extent, the size of these will be dictated by which brakes you are running, but the popular route of uprated XR2 brakes means you can still use 13 inch wheels. Plenty of aftermarket brake kits have been designed to work with 13s too so it’s a good place to start. However, you really need front-wheel-drive offset wheels, which are ET35 using the regular Ford 4x108 stud pattern and 63.4 centre bore — it’s tempting to use rear-drive offset wheels, which can look great but they do upset the handling, making the car tramline badly.
The best solution is good quality tyres in the 185/60R13 range — cheap rubber will accentuate over-braking due to less grip, so do yourself a favour and make it handle as it should — the tyres after all are the most important bit as they’re the only true contact with the road!
Going up to 15 inch wheels will give a wider range of brake kits and more of a chance of traction control off the line — but you’ll need to seriously watch the tyre profile, keeping them as close to the original or smaller rolling radius as possible. Even then, you’ll need to roll the arches for more clearance.
15 inch rims will fit fine, just watch the tyre profile.