dmjr

Hi guys,

Been scouring the forums here about modding and future implications, namely:

• Mechanical and/or electrical issues from an ECU tune (power limits on 1st gear of the 7 speed transmission, spark plugs, CELs -- always the chance of introducing new issues)
• High possibility of certain aspects of the CPO warranty being voided if a MB dealer notices anything that's "not stock" (drivetrain and whatever else the dealer wants to blame on an ECU tune)
• Issues or loss of value when trying to turn in, trade or sell back a car that has been modified (saw an interesting thread about this and once a car is flagged Status 8)

I've been leaning toward getting the "safe and reliable" Renntech ECU tune, as well as there sport mufflers for better sound, but have been reading how some RT authorized MB dealerships could potentially flag a car Status 8 after doing the tuning. Seems like MB is getting more aggressive with rooting out modified cars.

If I ever wanted to sell my car (i.e. back to a dealer), would it be possible to re-flash the ECU back to stock and have them put stock mufflers back on the car -- and still maintain CPO warranty status?

I'd think twice about this if it turns out I'd have serious vehicle or warranty integrity issues because of an ECU tune and a pair of mufflers (even if I didn't abuse my car).

Too much time on the forums and you begin to think about every possible situation.

Appreciate your input!

KEY08

kajtek1

Renntech is not cheap tuner.
Usually owners who want more performance sell E550 and buy AMG model.
Few years back somebody was posting ultimate sleeper for sale.
$100k for the base car, $40k in tunes, selling 3 years later for $29k.
I might be off from my memory, but not by much.

dmjr

It really wouldn't make sense to go AMG at this point. A '14 E63 with 40k miles is literally 2x the cost of my E550...

Tune is way more cost effective.

cocobeex

Turbo upgrade !!! there you go!!!!

rocky raccoon

Regardless of warranty issues, a modified car is always harder to sell. People in the used car market want to buy "stock". They may modify it themselves later but an already modified car has a bad "taste".

MBNUT1

+1

DFWdude

+2... No matter how well tuned and how nicely the previous owned kept it, a known "tuner car" carries the stigma that it has been raced, or treated as aggressively driven.

Some tuner cars are better kept than a stock one, but other tuner cars are definitely thrashed like a weekend rental from Hertz.

An astute buyer will steer clear of both, because you just don't know.

LemonSqueezy

My local dealer loves to give me a a lot of push back when it comes to warranty on my 550. It took a good 3 months back and forth before they decided to okay new engine mounts under CPO warranty. If there's any issues where your mods have any remote connection to your current issue you're looking to get covered under warranty, just be prepared to have dealer try to deny everything.

kajtek1

And for good reason.
The first "tune" young owners add is K&N filter.
When the filter makes less restriction in suction, it is letting more dust entering the engine. Would you like to buy such engine?
Tuning is very hot topic on trucks forum and for good reason. One of the best 7.3 l diesel Powerstroke engine left factory with 250 hp.
I read a topic where "tuning" was able to pump 1000 hp from the block. US-build engines are tuned poorly from the factory, so they do have lot of easy potential.
It ain't so with MB.

dmjr

Good feedback, guys.

Will probably stay stock for the time being.

Renntech and other folks/shops don't allow financing ($6k+ of mods), so not willing to pay up front (and risk car issues, lack of potential support) and toss my CPO until 2020 away.

Stock is fine.

LemonSqueezy

I gave into that temptation loooong ago, brought my car on a dyno recently and it put 506 lb ft torque to the wheels, and on a mustang dyno too!