With the tools I quoted I can only guarantee they all can program NEC chinese keys one time. Someone told me that some of these tools can also renew and program again these chinese keys, but I can not guarantee that because I never tested.
Remember I'm talking about random NEC chinese keys, not BE keys from noimmo.
BE key from noimmo can be written/renewed/read as much as you want by noimmo mbkeyprog and various other tools already.I'm not going to specify their names because I haven't tested them.
Regarding NEC EZS...
In this situation: EZS (NEC)+Working v51/57 NEC key, all these recent devices can add new keys, and most can also program new elv.
In this situation: EZS (NEC)+Working BGA key, the only device that can add new key/program elv is Diagspeed.
In this situation: EZS (NEC)+All Keys Lost, there is NO PUBLIC DEVICE that will add new key/program elv. The suggested solution is to buy a "virgin" EZS and adapt it directly/gray key(depends on tool). Myself, I think this solution is very expensive and would only be worth doing it if the car can absolutely not get new EIS from dealer.
Regarding w204 ELV...
First you need to know if ELV is not working only because of broken motor or also NEC disabled.
When you insert key on EIS, if you ear relay's "ticking" inside ELV it indicates NEC is not disabled yet.
If NEC IS NOT DISABLED:
-You can replace motor with a new one.
-You can replace brushes inside original motor.
-You can get a ELV from a crashed car from scrapyard and swap the NEC.
If NEC IS DISABLED:
-You NEED to get some information from the EIS/Key. (You always need a WORKING KEY for this situation, again, if it is BGA only diagspeed can do it.)
-After you get this information you have various options:
--Repair+renew+program the old disabled NEC. (only thelegendweb, simontouch and diagspeed can do it)
--Get a used (but working) ELV from scrapyard, renew+program it by plug connection. (noimmo, mercedesinstrument, diagspeed, necpro57 can do it)*****
--Program an emulator.
-Or you can go to dealer, owner must sign the papers and wait for the things to arrive(From a few days to several days depending on country).
Some of these solution involve opening/mounting/closing ELV which can be a hassle for many people.
*****You need to check that some devices/companies will charge you tokens to calculate files, renew units, etc.
Anyway, to me, my unbiased selection of the best device is Diagspeed, however I don't own it and not much people talk about it in this forum.
So you need to really know what you want to be able to repair and if it's worth to buy a 1k or 3k or 6k or 8k or 10k device for that matter.