The Zender 'Challenge' wheels were made both for the 145/146 (four stud), 916 GTV/Spider (5 stud) and 156 (5 stud).
Alfa Romeo part numbers from the Alfa 1999 UK brochure are as follows:
145/146: 60877754 (7x16")
156: 60877531 (7x17")
GTV/Spider: 60877472 (7x17")
These wheels are no longer available, since Zender ceased production in 2004. However I am selling my Zender Challenge wheels (see Avatar), these are the correct Zenders for the 916 Alfas, however I'm not sure how easy it would be to courier them to Aberdeen!
Like yours they are 7J x17 with part number 057075G, but with TA-294A (whatever that means). They also have 'e20' stamped on them, so will be the same offset as yours.
If you are interested in them, send me a PM.
Last edited by Spider95; 13-07-10 at 09:09.