I wrote that message. There are a few DIY updated and redesigned parts on early model W124's and 190E's. Mine is an 88. The radiater cap (now 140 bar), the thermostat housing (now metal I believe, mine is still plastic), OVP relay, e.t.c. I change my stuff just for peace of mind, I don't think there is any need to change yours unless you suspect a problem or are doing an overhaul of certain systems.