The difference between the Cup car and the Turbo S are big: some differences are listed here:

Wastegate
LSD
Exhausts (the cup car had three different)
The cars had 305 HP and 410 Nm, via a modified DME and KLR
Max RPM 6700
Magnesium sump,
Magnesium inlet manifold,
90W alternator,
stronger engine supports,
no power steering,
modified Turbo,
Bosch W 4 cc spark plugs,
no resistors in the fan circuit, meaning it goes full speed all the time,
Glued, riveted clutch disk,
modified gearbox cooling,
stronger gearbox supports,
30 mm front anti roll bar, 22 mm rear 3 way adjustable
Shocks, springs
drilled front brake discs,
switchable ABS,
Pagid S-535 brake pads,
front brake cooling ducts in place of driving lights,
8 and 9X16 Magnesium phone dial wheels,
no sound deadening,
no rear seat back,
1 driver Recaro bucket, 1 std passenger seat,
no glove box,
no radio console,
no door pockets,
no climate control (...),
no lighting for engine compartment or glovebox,
manual windows,
no rear wiper,
no rear hatch release,
no inner fender liners, except RF for ABS circuit,
rolled lips on 4 fenders,
thinner windshield,
honeycomb sandwich front hood, aluminum prop,
shock tower brace,
reinforced front chassis rails,
36 Ah battery, with racing cut-off,
8 point Matter roll cage,
Empty (no fuel) weight 1160 Kgs, about 2550 Lbs

There have been about 110-115 cars built all in all, including the first 220HP versions for 1986.