70 mm spacer sounds a lot..good site below for comparing effect of different offsets

http://www.willtheyfit.com/

Internet says 940 wheels were 25 offset & those jag wheels 61 offset. so a 40 mm space would bring the face of the jag wheel out 4 mm further than stock ones. I looked for some info on spacers increasing scrub radius vs handling also, not for scare mongering just for some thoughts on it.

http://rennlist.com/forums/racing-an...-handling.html