Hi, the list price was just over 200,000DM which was just under £70,000 back in 1985 so I think that requires pretty deep pockets as its about £180,000 in todays money! So if you mate did get one for about £9k to £10k (estimated cost of a sierra) it was a steal! In fact a stolen one should be more expensive.
Even a "normal" quattro was about £25,000 new in the 1980s and 11,000 of them were sold so why they would sell a Sport for that little is mental.
They were always highly desirable even though group B ended as there were plenty of Yuppies with cash to burn back in the mid 1980s!
So your mate got a superb deal at that kind of money - did he hold onto it?