Some 30+ US Mercedes dealers are also Renntech dealers. They sell the mods. It's maddening that this network is so randomly located. For example, there are none in California.

It's a Renntech development car, built at their facility in Florida and put up for sale recently.
Looks like someone finally bought it and brought the car to Nashville, that dealer did no work on it at all.

That dealer is one of the 30-so that also sell Renntech mods. It's not a coincidence.
https://www.renntechmercedes.com/ind.../north-america

Are the prices the same if you buy it through the dealer? I'm going to guess no... lol

it is

Some dealers do it because it is easy money for them but lets make it clear, none of it is sanctioned by MBUSA even though they are aware of that fact.
When there is a problem though, and they do find out about the mods, they slap Status 8 on your car faster then you can say Hail Mary.....

When does just an ECU tune like Renntech/Eurocharged/Weistec... what is the most common problem? All they are doing is adding a few pounds of boost in like 3rd gear+ right? To get an extra 80whp? What is the risk, throwing a rod? Do they even change things like timing in these tunes?

They absolutely change timings as well as boost. AMG engines are so strongly built, I don't think throwing a rod is likely. It's more apt to be something else failing from the extra torque, like transmission parts, flex disks, etc. Also, it's tough enough to get a CEL resolved with an unmodified engine. They'd have to find the "out" of a modified ECU very attractive.

I don't believe it's that simple, to be honest. Yes, some Mercedes dealers resell Renntech upgrades or Brabus or whatever, and yes, some will warranty those parts and say they will not void your overall car warranty just because you have said parts installed. However, if you blow up your engine (unlikely) or if you bomb your transmission (not nearly as unlikely), a Mercedes dealer will not go on out a limb to protect you from MB, as they could themselves get in trouble with MB. The only universal truths here:

- if you mod your cars habitually, just be prepared to have to come out of pocket at some point in your life (may not happen, but understand it's a real possibility)
- no dealer will sacrifice their relationship with MB for any customer, when it comes down to warrantying a large claim, where the failure was due to excessive power/etc
- if a dealer does choose to pay for your new transmission or engine, consider this an exception to the rule, and not the rule itself

I'm not trying to scare people from modding their cars, but it's important to understand the reality here, and not just 3rd/4th hand stories.

Tuning my cars has been my vice also, like you said, I just can't help myself.
I had my E55 blow up at 600 miles when on my way to dealer to install Renntech mods, God must have been watching me.
Fuel pump just exploded damaging the engine to the point it had to be replaced, there was MBUSA investigation and had it happen after the mods, they would wash their hands off (even though the fuel pump had nothing to do with compressor or ECU).
Dealer admitted that Renntech would not assume (rightly so) responsibility and I would have a long legal battle with MB that I would most likely lose anyway.
The bill (in 2003) was $44k.
Btw, I did not send the parts back to Renntech, told dealer to keep them and later installed them in the repaired car with new engine.

Brass ***** for sure under those circumstances lol. Can't say I wouldn't have done the same

> where the failure was due to excessive power/etc

Does upping boost and changing timing to add 80 peak whp really classify as "excessive power"/what can really realistically go wrong from a simple flash/OBD tune?

On top of that, that's the *Mercedes* warranty. Didn't Renntech make the genius sales move to have their own warranty through them, on top of the Mercedes warranty (which we are all hypothetically is 100% blown if you flash your car and experience a complete transmission + engine failure?)

https://www.renntechmercedes.com/ind...customer/faq-s

​​​​​​​Excessive in the sense it is beyond stock. Anything can go realistically wrong.....I needed a new trans with a tune only setup. Figure out what/who you're willing to put your trust in, and do something, or not.

What model/year/tune? That's quite interesting to hear.

I blew my entire F10 M5 engine but it was manual and I drove it hard as hell and I had a JB4 on it for a few days before I said f*ck it and returned it because that ***** broke down on me in traffic in 95º heat and I had to push it across 4 lanes of traffic while a cop yelled at me like it was my fault lol

Lol. Yikes man. 2018 e63 with weistec tune. Was at drag strip. There have been a handful of tranny failures in the us on this car...tuned by various folks. New transmission is holding up just fine with more power and at drag strip, so, must've been a bad one destined to fail...

Did it fail while you were launching it? Did they give you any trouble because it was tuned? How much was the new tranny + labor to install it? Did you have to pay any of it?