Whilst I am biased, I love them and think they suit most period cars. Let alone when you consider how uncomfortable those flat merc seats are. Electric or not.
As for a half leather set, I assume you mean the 16v dogtooth? I may just know of a pair of half leather half dogtooth recaro classics that will be for sale in the near future...
Correct, the seat belt has to be inbuilt into the frame for the R129 as it has no seatbelt mounting on the b post.I'm not sure after market Recaros were ever offered with this feature.