2003 W209 CLK, 2005 R171 SLK, Volvo XC40 P8 Twin Motor Pro EV
I have a covercraft weathershield HP for the 124. Seems to work well. Its said not to be totally waterproof but breathable. So far I have never found any water under the cover. Its left in place for up to 10 weeks at a time.
Totally agree. Ours is only ever put onto a clean car and left for several weeks. It does a great job of keeping the sticky tree sap off the paint and bits of seed/leaves out of the drain holes.
I had a Covercraft Noah on my SL for a couple of years. It's important to get a fully tailored cover for a snug fit ... otherwise they move about when the wind blows and will eventually mark the paintwork (particularly if there's any dirt on the car or cover). Breathable is best.
They're not cheap, but my cover was still in virtually perfect condition when I sold it to a member here (after we moved to a house with a garage). I would certainly recommend Covercraft, they even have different versions depending on which door mirrors (rectangular or oval) your R129 has!