TRANSMISSION

Quaife ATB (Automatic Torque Biasing) differential gave the RS its reputation for pin-sharp response but somewhat rowdy behaviour; on the test-drive, you’ll notice a tendency to tramline and follow road cambers, but later cars had less-aggressive differentials, so it could be worth trying out a couple of cars before buying.

The diff is durable, and the MTX75 five-speed gearbox – uprated for the RS with close ratios and shot-peened cogs – is unlikely to be exhibiting much wear. Check for crunching when changing gear (suggesting synchromesh failure thanks to hard driving) or terminal whining – possibly the result of allowing the transmission fluid to overheat; trackbuilt RSs are often fitted with gearbox oil coolers to avoid problems.

The stock RS clutch can handle 300bhp, but will start to slip with abuse or high mileage. Check it isn’t slipping under load – especially on boost. Big-power cars will generally have a paddle clutch, which will give your left leg a good workout in traffic.