Geoff, how you doing man?
The swap cost varies by too much to list a set price on the forum. There are lots of options, from whether you want to drop everything in 100% as-is, to a basic Ins II freshening, to an all out replace-all-seals-I-want-this-thing-showroom-fresh type of swap. Of course, which of those motors you choose is a huge factor also as the S50 requires less labour and parts to work in your '95. Same deal with the transmission, do you want to keep your Getrag or move to the stronger ZF that the M3's came with? And so on...
Drop me a PM with your specifics and we'll take it from there. I promise we'll be the best value and be proud to put our name behind your swap.