I'm fitting Spax springs and adjustable shocks to my 280E, like these:
http://www.larkspeed.com/index.pl?p=SPX88P074&a=iYou just need to buy, or borrow a spring compressor to fit them, like this;
http://www.ebay.com/itm/Mercedes-Benz-Coil-Spring-Compressor-Suspension-Repair-Tools-Kit-/250968104178?pt=Motors_Automotive_Tools&vxp=mtr&hash=item3a6edd5cf2#ht_2424wt_958I'm also planning to cut my springs, seeing as I've stripped out my car for track use, and it's now 500kgs lighter, so the lowering springs are still higher than the original, standard ride height!!

EDIT: I nearly forgot, you'll need to get a drill mounted sanding flap wheel, and clean out the holes in the front inner fenders, or the spring compressor won't come out of the springs, it only takes 10 minutes to do.