Just a heads up, your '86 930 would have originally had a "tea tray" style rear tail. The 3.3L 930s ('78-89) all had the tea tray style to incorporate the intercooler. Only the early '75-77 3.0L 930s had the whale tail style lid, though often people use "whale tail" generically.
You can see pictures of the different tails here:
Whale Tail vs. Tea Tray Spoiler