Yes owning W124 E220 has been really pain(more) and pleasure for me.
I can say W124 is very well supported, dedicated international forums with lot of information, very experienced MB Tech's who go out of the way to help member's. This is the only experience that has been pleasure for me.
Some of the forums I regularly visit are
1)
Tech Help - PeachParts Mercedes ShopForum
2)
E-Class (W124) - MBWorld.org Forums
3)
W124 E,CE,D,TD Class - Benzworld.org - Mercedes Benz Discussion Forum
I bought a W124 that had everything wrong with it, You can imagine a problem and I have already had it

. I keep thinking about writing my experience, which should really bring out small and big things involved in maintaining high end cars in India, where demand exceeds supply( I mean one authorized garage for a city like Bangalore, it’s literally a stampede out there every day ). Even though I owned it for 1.5 years, I feel I have spent 15 years with it.
You can search my posts on
Tech Help - PeachParts Mercedes ShopForum with same ID as team-bhp, where I have asked for help with some of my problems.
One of the my greatest experiences was this
HFM Scanner (For 111 and 104?) by Misha... - PeachParts Mercedes ShopForum , I was desperately searching for ECU coder, since my ECU was coded wrongly and asking dealer didn’t help (err actually at that time I fought with the service manager for a poor job done on my car).
I posted for help in one of the Russian forums and someone with ID Misha became GOD for me @ that time. He suggested he had a software that could read ECU info and mailed it to me. It needed particular interface which I didn’t have, instead I ran the software with Chinese Carsoft interface which was similar but didn’t work. Since I knew how these things work I captured debug info and sent it him. He modified his code and sent me a new copy, voila it worked with Chinese interface. Again back to the problem, I could only read the live info from ECU, but could not re-code it. I just had to ask him can please make this software to re-code, well he was on it. We exchanged may new version of software and debug logs, Misha figured out that there were few security in place to prevent un-authorized ECU re-coding. One was valid workshop ID was required to recode, next was some security key/password was to entered/sent by interface to for ECU to register the new code. I think workshop ID will help MB to track which workshop re-coded the ECU, we decided to pick the workshop ID which was already there on the ECU.
Next thing was to get the key, which Misha figured out was some combination that had to be brute forced, well my remote testing help was of no use here and he didn’t have a W124 E220. But this ECU was common between many MB four cylinders at that time. I think he sourced one of the ECU from scrap yard rigged up a minimal interface to power the ECU and connect diagnostic interface and ran crack again it. In two days I had a test software to try, this had re-code menu, but new code I wanted was hard coded in the software. On clicking recode menu this would brute force set of security key/passwords to make ECU accept the code, it worked on the first try. It was a great feeling finally, great in the sense
1) I was being helped someone whom I didn’t know, I wouldn’t pay either.
2) Misha can barely understand English.
3) Whatever I wrote in English, he translated it to Russian using Google and replied back.
4) His replies where actually written in Russian but translated to English before mailing me.
The software was in Russian, I convinced him to translate it to English since it would help many W124 MB owners, and that is
HFM Scanner (For 111 and 104?) by Misha... - PeachParts Mercedes ShopForum
Well this is one of my experiences out of say 100, each one of them had some adventure or the other with lot of money spent. Well do I love driving this train, YES, I would love drive it 24/7 and most probably my next car will be W124.
What I can say from my experience is in India a good MB tech is rare, availability of parts and other resources make it worse. Knowing your car and DIY will go long way in helping a trouble free ownership. I was always a DIY person and had basic tools for wrenching already. I even have DAS @ home. So anyone in Bangalore need to use DAS/EPC/WIS or above interface you know whom to P.M
P.S: Hey Ravindra want my Car, its W124 E220, wait let me replace the differential and CV axles and get back to you
