The suspension components on the top end are the same and directly bolt on; however, it is the wheel carrier end that does not bolt up, at all. Reason, the bottom of the strut for 987s is about 1/8" wider, hence, the bottom of the strut will not slip in between the 986 wheel carrier.
As a result, one would have to replace most, if not all, lower suspension components... from wheel carriers to hubs, bearings, etc. And even then, the 987 strut is still taller. By how much, I am not certain as I haven't had the opportunity to obtain this info nor measure the difference myself.
I am currently working on potential suspension swap solutions and will let everyone know as soon as I learn more. The main reason for becoming interested in such a inquiry is because not many manufacturers are including the 996 and 986 chassis to their modern suspension builds.
Moreover, the 987 and 997 are the closest parts for such a project and for the record, the 987 and 997 have stronger chassis and suspension components than the 996s and 986s, and if the parts were interchangeable, they would make a great update for 986 and 996 owners.
As an example, the attached image shows all the parts that would hypothetically need to be swapped out for the 987 suspension to fit onto a 986 chassis, but we should also remember that the total suspension length (end to end comparison) is still a big issue and geometric challenge (as I mentioned, the 987 strut is a tad bit taller, which can significantly make a world of difference in performance and ride quality).
I hope this information somehow helps those of you who are interested in this subject!
Happy New Year! Cheers, MoMo
