Yes, a few people at mbcoupes.com have converted to conventional springs. Search their archives and post any questions you may have on their BBS.
It is either Bekkers, or Performance Products (don't remember which)that sells a plate to cover where the hydrualic pump was once you remove it. You can just lock the leveling valve and plug the ends of the hydrualic lines if you want to convert back some day. Cheers, Andrew Seidel.
85 500SEC Lorinser
83 300D Turbo