Kent's tool is a bit expensive for a one-shot deal, but I've used it on 4 cars now and have also let Fonzi borrow it. The one up in the tunnel is easy-peasy, it's the other one that isn't fun. The brass clip tool that comes with it is even better though as I've used it on throttle linkage clips, and it looks like it would work on a lot of the rod clips in the R107 soft tops.I just did the ones on my 85 300D.
I am sure Kent's tool helps, but it is a bit expensive for a one-shot deal. On PP, someone suggested using a cherry pit punch! Something like this:
After trying the one in the tunnel, I decided to remove the lever on the side of the tranny as well as the shifter itself and do them on the bench (Used vice) Went in easily without lube or heat. Many suggested boiling in hot water, especially if doing the shifter bushing up in the tunnel. Silicone spray would no doubt help.