The third model, the higher specification F78 TDX, on the same wheelbase as the TDL, passenger only, was fitted with 7" alloy wheels, 255/70 tyres, and as result was fitted with additional resin arches, secured over the top of the steel wings, to allow for the extra width. A TDX is 100mm (4") wider at the arches than a TDL, not allowing for the door mirrors, and can be identified by there being a seam seal over the top of the arches.