I'll try and help you as much as I can. Their site is all in German and I have translated the salient points for you below. I hope it helps you.
Before I go on, I want to make it absolutely and crystal clear that I am not connected to this company / selling ANYTHING / touting / vending / advertising / endorsing / nor getting ANY financial gain from AT ALL from this company. Nor asking for opinions on it. 😥 Phew! Is that clear? I'm doing this to help the community, purely and simply. There is a lot of information in German on the German websites over here and sometimes it's frustrating when you can't understand it. That alone is my motive.
I researched it a lot before I pushed the button. There's a lot of forums over here which gave good strong feedback on Speer - and not just Mercedes forums. 😆
For you sceptics, don't read on. For gianp, since you asked, here goes: this is under their FAQ section on their website:
Their web address: click here: Echtes Chiptuning ? In Baden-Württemberg ? Motortuning ? Leistungssteigerung
email address on their website is: firstname.lastname@example.org
You'll need to tell them your make and model, and which size your existing crank pulley is. 193mm or 185mm. Ours was a 185mm. Don't know what yours is.
Das KompressorKit inc pulley and belt and ECU remap. You can just get the pulley and belt.
Option 1 - Tell them your ECU number and they'll send you a pre-programmed tuning chip specifically for your car for you to install yourself. This usually involves some soldering. Instructions with pics are included. (OK if your German is good!!)
Option 2 - Send them your ECU and they'll do it for you. Normally 4 days (for Germany). You pay shipping, of course. Checked on their ebay.de listing - 16 Euros shipping to Italy - DHL. Might be more. Search on ebay.de for Speer Chiptuning and their listing will come up.
Option 3 - Arrange an appointment to go to Heilbronn in Germany and they'll do it. (Not an option if you're in Italy, I presume?)
Option 4 - They can "lend" you the OBD programming device and you programme it yourself at home. Instructions included. + 49 Euros. You need a laptop with Windows. You can buy the OBD programming device for 89 Euros.
There's loads more info on their website. There are, of course, other tuning companies available. I can only give you the benefit of my personal experience with these guys. I had this done in May 2015, prolly 3 or 4,000 kilometres ago and I'm still trucking! Very happy with the results.
Sacha was the name of the guy I dealt with. I did it all in German. He may be able to do this in English. I know some other members have done / are doing it and they're English speakers.
BTW.....got her up to 240kph today
- nowhere near red line and she still had some oomph left in her but I had to back off cos of traffic 😢
Hope that helps! Let me know how you find it once you've had it done. Interested to know.