I purchased the "OEM" brand spring compressor, but its not long enough for the regular w211 springs.
I need a compressor that is longer. This is for the front regular struts - McPherson style.

What have you guys used before that work?

 

Honestly I just took my struts to a shop that had a floor mounted strut compressor and paid them 30 minutes labor to build the front struts for me. Some of the best money I have every spent as it was like $50. So unless you are changing springs or struts often I would just go that route. If you are doing it often spend the money on one of the floor/wall mounted compressors but from what I am told they are not cheap.