hi there, I am also looking at a set of porsche seats in my golf, from what I can see they are 924, or 944 seats, but maybe not recovered in snake skin though (E38 picture I guess).
boxter seats also look nice, you can get a pair of ebay for about 350.
The advice that I was given was to get some vw subframes welded onto the porsche bases, dont know if that would work with electric adjustment though, I would be interested to find out.