Here is a solution for installing 987 memory seats in a 986 with minimal re-wiring. Works great and I’ve run it for the last year.
Note that a manual 987 seat can be installed more easily, but the comfort seat won’t work without the approach below (simple microcontroller for CAN commands) which is very straight forward or a more invasive full re-wire of the seat motors.
This GitHub article covers the full build.
Works for 987 memory seats in a non memory seat 987.
Also works for 987 seats in a 986.
997 and 987 are interchangeable, so are 986 and 996 wiring.
All 4 have the same bolt pattern.
https://github.com/trudant/987-997-Comfort-Seat-Hack/