Oldie but (very much) a goodie!
I had a chance to be the second owner of this great E-class specimen, and am glad I took the opportunity.
My family has traditionally been an MB-owning family, but I have personally never owned one.

Now that I have become an owner, I have found a few items that I wish the car came with, but the rest of the car more than makes up for it.
Allow me to share (for your reading pleasure) my impressions from the initial period of ownership.

5.5 Litres is a great thing
Just knowing that you have so much naturally aspirated torque and power is great, and I feel like I do not need to rush things anymore as compared to my 2.3 Litre Swedish rocket. It's buttery smooth and the Manual mode turns the graceful beast into a "stabbed" beast.

5.5 Litres is not such a great thing
In Manual or Sport mode, I might as well be pouring premium petrol onto the road. How does anyone get above 20mpg?

Modern conveniences that are (sadly) not present
Things like blind-spot warning lights in the side mirrors
Reverse camera guide-lines
Trunk closure button
Bluetooth music streaming

Some great conveniences found
Adaptive High-Beams (really neat)
Distronic cruise control
Sport seats are infinitely adjustable - such luxury...

Some features I'm still looking for
"Repeat" on tracks played on media would be nice. Yes. I'm the type who can listen to a single track over and over again.
Potentiometer to adjust the brightness of ambient lighting (door latch, ashtray, footwell, mirror-down-lighting, etc.) and the illuminated sill
A way to calibrate the parking assist warning - it screams at me a bit too late (luckily no damage yet)

Maintenance to look forward to DIY-ing in the coming weeks
Lube & filter (A svc.)
Main fluids (B svc.)
Change brakes to semi-metallic pads (currently ceramic)
Adjust parking brake (drums) to be tighter
Change air filters to permanent types (e.g. K&N)
Change tyres - Driver side tyres are from 2010...!!!

Modifications a bit further in the future being considered (but may never happen)
Much more aggressive brakes & rotors (e.g. Brembo)
Thicker anti-roll bars
Window tinting (for medical reasons - really)
12" Android touch-screen to replace current display (from CKM)
Steering wheel update to 2014-ish era
Mild suspension (air or static) change to erase fender gap

I'd like to give the E550 a slight bit more agility to carve the backroads without so much roll. I understand that it is a considerable amount of mass to move around, but I'd like to tighten things up a bit while retaining the smoothness; I'm aiming to keep the graceful character of the E550 as much as possible. Frankly, I neither need speed nor horsepower (NA'd 382hp is plenty). If I need to go fast, I'll just hop on my bike - there's plenty of power and speed to be had there.

I'm really enjoying the process of getting to know this car.
I missed being in a car designed to be graceful - and this coupe is everything I need and then some!

 

I mirror your take on the '11 E550. Also an old fart (70)

I've had mine for 8 years (a lease return with 15K miles).
- Installed LED interior lights and fire extinguisher
- Replaced stock grille with SL sport grill
- Replaced stock brake pads with Akebono EUR1341/1342 ceramic pads.
- Originally replaced stock Pirelli P Zero Nero All Season M&S with Bridgestone Potenza S-04 Pole Positions (235/40 & 255/35).
When Bridgestones aged out (6yrs with 17K miles) replaced them w/ Michelin Pilot Sport 4S (slightly larger 245/40-18 & 265/35-18 to
address the fender gap and increase grip).

For tunes, I plugged in an iPod with 350+ CDs - '70s to current music. Aside from a faulty tire pressure monitor, it goes in for a brake bleed every other year. I've done the routine maintenance.

Mainly our trip car. As for mileage, on trips on Hywy 5 to SoCal with cruise set at 85, it gets 25mpg. Drops to 24mpg if I bump it up to 95
Enjoy your new ride - ;>)

 

Thanks for the share - cheers!
Similar situation here - took ownership last month with 17K on the clock. Yes, a 10-year old car with 17K miles.
Sergio, did you install a full fire suppression system, or is there a small extinguisher in the cabin? Did you opt for Dry or wet? Don't ask me why I'm so curious
I've also been looking at the Michelin S04; a great set of skins. Love the 'stones but they tend to wear a bit fast, from experience - so fantastic, I'm a 'stoner on my bike (Battlax S22 for those who may care).
One reason I'm going the Android display/computer route is that I want AirPlay for my Apple-poisoned family.
Speaking of which, I might try to snake in a wireless charger right underneath the rear passenger console tray area at some time, for my girls.

Tschüß,
James.

 

I installed this under the passenger seat (I've got an extinguisher and V1 radar detector w/ dash mounted remote display in all our vehicles):

https://www.rennline.com/Rennline-Fi...E13%2E15%2DH3/

In addition to the S grill, I also swapped out the stock exhaust tips for the AMG twin-ovals (+5hp on my butt dyno).

 

That is a great addition. Rennline is very reputable - good choice!
I see that you own a GT3, so it makes perfect sense
Also, their choice of Halotron 1 is great for fire suppression with minimal loss.

Does the bracket require much modification to fit?

 

Slide the seat all the way back, remove the front rail bolts, lift the rails up a bit to slide the bracket under them then re-attach the bolts.

 

Fantastic - Since there is no mention of MB in the non-Porsche applications, I was wondering if it was a direct bolt-on application.

 

I'm not that old of a fart.....57 in a couple months. I struggled for about 8 months between 2010 -11 E550 coupe or 2012-13 E550 couple. I drove as many of each to get an idea. I prefered the cosmetics of the 10-11, but the functions and drivetrain of the 12 - 13 won me over. I LUV the looks of the 14 ups....but no gear shifter in a coupe....nope....nada. I still miss the simple operation of my 2000 CLK 430....no bells and whistles, but HUGE permagrin whenin sport or M ' modes!!!