Difficult. The E32/E34 have unique hooks up front; most other cars use four studs out of the floor. So, you'd need custom brackets to account for that, and for the difference in width between E36 and E34 seats. Then there's the harness connectors, which are a minor issue after handling the earlier stuff.
EDIT: actually, now that I think about it -- isn't there some guy on ebay who sells the brackets to install E30 seats in E34s....that may solve a lot of issues.
If I were going through the trouble, it'd be for a set of E46 M3 coupe seats with the adjustable side supports. Otherwise, the E34 sport seats are okay. And I love my plain jane comfort seats.
best, whit