Steven,
Having just gone through this:
The OEM seals from MB are a must for: Windshield, Trunk, side window front channel along the A Pillar, and soft top lid.
The curves molded into the rubber for the windshield and trunk make installation infinitely easier, and the seal more robust. The repro's have no such molded corners.
The soft top lid has a felt section what the front of each side which protects the soft top rub spot when folding in. The A Pillar window rails have a mesh built into them to allow the window to operate more smoothly than the Repro.
As for the door seals, I thought the repro "URO" versions were fine.
Hope this helps. If so, please consider joining as a member. Advice like this will save you lots more than $30 per year.....
Mike Mizesko
(Born at Mercy Hospital by you a long time ago)