www.preformanceproducts.com has a valve spring compressor in their new cat. on page 69 for $180. Its a bit much for a not very frequently used tool. With the picture and measurements from your cyl head you might be able to make one if you are moderately clever with tools. Its a shame that mercedesshop .com does not have some sort of tool rental system. The prefromance people have some tools to rent like a suspension coil spring compressor but if you want to compress valve springs it is of little use. Then again with a bit of modification......