They should fit right in harness wise. You would only need to switch plug ends if you are putting in the Euro variety which are Hx based, not 900x based.
You'll want to plan to replace the 3 adjuster / mounting screws as part of the swap over. They are typically frozen from age and the plastic tabs are hard and can break when you swap. Good item to source from the dealer; it's hard to figure out what's what in ETK. About $4 each if I recall.
Plan to take the nose of the car apart to remove the headlight mounting bracket. Bit of disassembly.
Bellevue WA
90 535iM - not much stock remains. 3.7 liters, ported head, cammed, 3.73 diffy, M5 brakes, MAFed, yadda yadda yadda
86 Porsche 951 - Track Toy