I put late leather seats in my dad's 1990 300D. Make sure the tracks are properly aligned, I had one that I initially thought the frame was bent due to the holes not lining up but then I realized that one track had slipped when I was powering them with a drill battery at the yard. I reset them and it fit fine. You should be able to switch over motors and controller and harness from memory to non-memory seats if needed, or even use the tracks or frames from your current seats.

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Current: 1975 450SEL, 83 300D, 88 Yugo GVX, 90 300D OM603 swap, 91 F150 4.6 4v swap, 93 190E Sportline LE 3.0L M104 swap, 93 190E Sportline LE Megasquirt, 03 Sprinter, 06 E500 4Matic wagon.