>that the cars after 1991 are more expensive.

More expensive? The early cars were V8 Exklusiv only!

The cheaper V8 with velour-seats and missing climate control were available from 1991.

For parts I would prefer the V8 with the best overall condition (in relation to a good price)- independent from its manufacturing date. Especially with S8 engine and tiptronic transmission in Pertuu's case. The changes after 1999 were minor and mainly affected the control units.

Maik