Sometimes it really feels good to spend money on yourself. But its very unlikely that at 100k you need anything more than some plastic chain rails.
The Euro cams are probably different and they shouldn't have reached half-life yet. If it ain't broke don't fix it.
If you really need to improve something replace the chain too, but they easily go 200k if they don't have to run over broken rails. (Broken/jumped chains are probably due to broken rails at least 90% of the time)
Owner 24 bay BSC
Bosch Master, ASE master L1
26 years MB technician