Heres some information on wheel fitments that may be of use.
Its a list of OEM wheel fitments suitable or adaptable to the T3. Where suitable I have added notes on work needed to fit them.

AUDI
Model P.C.D. Offset C/Bore
100 (90>) 5 x 112 35...42 57.0
A4, A6, A8, V8, S2, S4, S6 5 x 112 35 57.0
Notes: Offset usable but small centre bore diameter means a need to machine the front wheels.

FORD
Model P.C.D. Offset C/Bore
Scorpio 5 x 112 35...38 63.3
Galaxy 5 x 112 42...45 57.0
Notes: Offset usable but small centre bore diameter on Galaxy means a need to machine the front wheels.

MERCEDES
Model P.C.D. Offset C/Bore
All (except below) 5 x 112 35...42 66.5
SL models 5 x 112 18...25 66.5
A Class, Vito 5 x 112 45...50 66.5
Sprinter 5 x 130 45
Vito/ML 16"x6.5J/PCD 5x112/ET47/Bore 66.5
ML -2/2002 16" 5x112 62 66.5
ML 2/2002- 17" 5x112 52 66.5
Notes: Good choice of usable offsets, centre bore adequate. Sprinter wheels require Porsche adapters. ML wheels require spacers, particularly at the front due to offset. Reports coming in that ML wheels use the 14mm ball taper standard.

PORSCHE
Model P.C.D. Offset C/Bore
911, 924, 930, 944 >86 5 x 130 25 71.5
911 Carrera 2/4, 928, 944 87>, 964, 968, 993 5 x 130 45 71.5
Notes: High offsets but with adapters many choices of style available.

SEAT
Model P.C.D. Offset C/Bore
Alhambra 5 x 112 35...38 57.0
Notes: Offset usable but small centre bore diameter means a need to machine the front wheels.

VOLKSWAGEN
Model P.C.D. Offset C/Bore
Caravelle, Passat 96>, Sharan, Transporter 5 x 112 35...40 57.0
Notes: Offset usable but small centre bore diameter means a need to machine the front wheels.

and i've got a set of jag wheels on mine at the moment!! they fit straight up!!