I'm not sure an engine that develops maximum power at 7000 rpm could be called "unstressed". It does seem to be a tough unit though, plenty of leggy QPs around after all. This car is surely headed for the bargain basement unless bought as a keeper.
The missed service is worth investigating, if it is just a missed stamp in the book. I'd want the lease company print out too, they will fax it if requested, my 159 had two missing stamps but one short call and bingo, full history!