I know this is not an economy car. I don't drive slowly, and I am enjoying the acceleration of this 01 E55. However I am very impressed with the gas mileage of this thing! I do mostly highway, so I am sure that helps, but over the past 1200 miles I have averaged almost 23 mpg. Even more impressive is that it's doing this with 246k miles on it, with enough power left on tap to put a serious hurting on an 07 mustang gt with a manual and a couple mods.
We are already thinking of picking up another to have a "his and hers"

 

+1 I totally agree, I've never had a car 14 years old that'll get the gas mileage this one does. My average is about the same. For a daily driver that makes at least two trips into the city from the suburbs of Chicago (106 miles RT) and at 144k miles, I'm more than impressed!

 

I have my mods for almost a few years now and every time I get in the car, it always wants me to step on the gas. My headers and exhaust noise are pretty prominent now as the engine has already adapt to them. At WOT, you can hear the engine scream as it shift thru the gears and all the rice rockets and bimmers would try to get side by side wanting to race you. I'll miss this car if I ever replace it.....

 

Snoozie, You pretty much have the exact mods I have planned. The only addition I really want over what you have is a quaife rear differential. This car really doesn't need much to be faster than 99% of the cars you'll meet on a day to day basis.
I really like how it is very understated in the looks department vs its performance, while still looking nice and classy. The only hard part about owning it is not the higher maintenance cost, but keeping the keys away from my fiance' lol she loves it too.

 

Midwest - I did an experiment with my 2001 e55, complete stock with about 124k miles on it. Driving from the No.Colorado area to Denver and back. Involved about 15 miles of non-highway driving and about 120 miles of interstate at about 75-80.

Conditions:
Alt: 5000'
Cold start
Normal driving (as normal as I can get with an e55)
Air temp - low 60s
Tire pressure - 39 front 42 rear
Driver plus one passenger.
Total mpg at end of trip: 25.6 (using car's measures after reset before start). While this is lower than my 1998 e430, it was higher than I expected - BTW this is better than my daughter's Maxima with a 3 liter v6.

 

^wow I definitely believe that the AMG M113 NA engine is very well built and more efficient then most engines. My 02 beater Subaru outback is a very good example. That car is very bad on gas mileage as given that it has no power what so ever and a 4 banger and it gives around 19 to 20 mpg around town. Only good thing about this car is the 4 wheel drive. I'll have my E55 any day

 

My fiance recently took it to go to a doctors appointment about 80 miles away, when she got back she just had to brag that she got better gas mileage out of it than I do. I looked at the little mpg readout in the dash and sure enough she did! 24.8mpg avg over 165 miles.

Our other vehicle, a 1998 Honda passport 4x4 gets terrible gas mileage. It has a dohc v6, 4 speed auto, and weighs about the same as the E55. We have only managed to get 20.1 out of it once, but usually its down around 16-17mpg. I guess that's not bad for a suv on all terrain tires tho.

I was really hesitant on buying this E55 with such high miles on it, despite it having 246,000 miles, it is getting great gas mileage, the paint is still shiny, the interior literally looks new, every single thing on it works and it can still get down and move when your right foot calls for it.

The passport with almost 80,000 less miles has aged well too, but the paint has some fading, the leather has hardened up a bit, everything works in it as well but that is because I dumped a bunch of money into it last year lol..

Just goes to show that the build quality of this car is excellent, and the original owner took very good care of it, as I plan to do as well. I hope than I can spin the odometer up to 346k.. We shall see!

 

Colorado to L.A. and back, averaged 24.5.
On one tank I got 26.6.
This is calculated not using the car display.

The one time a week I drive it to work, 61 miles each way, the display indicates 24.8.

My wifes VW Tiguan gets 24mpg.
My modded Mini Cooper S gets 32-35, but I can't resist driving it hard