It looks to me from the photos (obviously photos can be deceiving) that the motor part is the same size on both. The Bendix section is shorter on the reman, making the overall length shorter.

FWIW, the reman in my SDL is the same style as your reman, complete with the 8mm stud on the relay and it's been working fine. Was an Auto-Zone rebuild installed by the PO and had the solenoid drowning in axle grease, but that's another story. Cleaned that mess off and it's been solid. With all of the engine problems I had last year that poor thing's lived a REALLY HARD life. If it was going to give up, I'd have expected it to have done so by now.

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Current stable:
1995 E320 157K (Nancy)
1983 500SL 125K (SLoL)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

Gone and wanting to forget:
1985 524TD 167K (TotalDumpster™) [Definitely NOT a Benz]