So part one dealt with. The two front AMG wheels are off, replaced by a spare A4 steel (doesn't fit properly, held on solely by tension from the extra-long MB Bolts) and a spare MB steel from an old E-class (which again doesn't fit properly, the baloon-section olde tyre fouls the suspension arms). So the scrappage car (an immaculate '98 C230Kompressor Sport with 69k on the clock) can't be driven any further than the back of a car transporter.
The two rears are next, we've found a pair of brand new ex-display MB alloys which have to be scrapped, we'll bung a couple of scrap tyres on and the C230 will be consigned to oblivion with four non-matching wheels. Fun times.
So:- Jobs to do (After renewing hub bearing, my task for Sunday)
Obtain Spigots from the 'bay
Obtain longer wheel bolts from the 'bay
Use immense machining skill to bore out the mounting holes a little for proper, manly Audi bolts.
I had totally ballsed up my concept of offsets and got it all the wrong way round. I'm guessing that 37mm offset will be less close to my suspension metally-bits than my exsisting ET42s. This should mean that the front wheels will appear 5mm wider in the arches.
The rears will be interesting, the combination of 5mm less offset and half an inch extra width should give me a real wheelarch full o' rubber. Again, I'm guessing I won't have any fouling problems with rear suspension, my exsisting ET42s are wearing 235 rubber and there's plenty of clearance.
Watch this space. Thanks for all your help so far.