Wow, the people in this forum give you much more meaty advice than the MBCA tech forum. (Most of their participants only seem to know about wheels, tires, stereos and alarms.) Thanks for your suggestions.

I just ordered a clone of MBZ tool #202 589 00 43 00 from a supplier on eBay for around 90 bucks. Hopefully that will do the job.

I was able to remove the spring without a compressor by supporting the outside of the lower control arm with a hyd. jack, unbolting the lower pivot (21 or 22 mm bolt/nut), then very carefully lowering the control arm. Just for kicks, I tried re-installing the spring by reversing that method. But that didn't work for me. The spring pressure tended to push the lower control arm out of line (in the fore & aft axis) with the lower pivot bushing, & I was unable to get the pivot bolt reinstalled. So, I decided to rent a proper spring compressor from www.performanceproducts4benz.com. They charge $85.50 for 3 weeks of rental.