When you hit that button is ESP 100% off? I think somewhere I read that it's not quite 100% But I could be mistaken, or the source was wrong....

Yup...100% off...The problem a lot of people have with it is that it's EVERYTHING off...No toggling ESP off and leaving TC on which does kind of suck, but like we've all been saying, It's not a Porsche. Short answer, yes everything is off...

So everything is 100% off? I always thought some of it was still on no matter what. I've only driven on the street/parking lots, etc., with ESP off and so I couldn't ever really get to feel if everything was totally off, but it didn't really feel like it was(?) I also thought if you hit the brakes then ESP comes back on (?)

The manual says when you switch off ESP the "ETS will still apply brakes to the spinning wheel" and "the ESP operates while you are braking."

Edmunds IL once said this: "Acceleration Comments: Typical Mercedes traction control meddling despite ESP off."

I also found this review of the E63 on EVO UK and maybe that's what I saw some time ago(?)

"Of course, there’s ESP acting as a silent and almost undetectable guardian angel – isn’t there always in 2006? – but it has an off switch. And although it’ll still cut-in should it think you’ve run out of talent, by then there’s a good chance you’ll have just punted two-tons of Benz through a hedge. Backwards."

"Like an M5, the E63 is a great entertainer should you remove the first layer of ESP."

Although I agree to run in ESP off mode for the best lap times, assuming you have some track experience. When you hit the ESP button inside the cabin, the electrical nannies are STILL on.

The ONLY way to completely eliminate the ESP nannies is to run in DYNO mode.

However, you will loose your ABS as well I tired this in a C32 at Beaverun, and it was NOT the fastest way around.

So ESP off, and deal with the nannies in the background, provided that you have some track experience, IMHO.

Have fun out there guys, and be safe

That was my understanding, too.

So how do you deal with it on the track if every time you hit the brakes, ESP comes on? If the button is off, does it go back off after you release the brake pedal?

I don't quite understand your question, as seldom, IF EVER, have I had the ESP light come on when hitting the brakes hard

Usually it only comes on when punching the throttle, or trying to go TOO fast around a bend.

Now in the rain, on a hard brake check you could get it to come on, but on try pavement I doubt it.

As far as the ESP button is concerned once you have it off and the little triangle is lit on the dash, it stays OFF until you hit the button again.
IF the ESP does function, read electronic nanny here, while you have it off, then yes it does shut off again after it corrected whatever it didn't like.

Sounds a little confusing I know, but on the track it works well.

Again, I do remind everyone here that IF you are a rookie to road courses, PLEASE leave it ON until you are comfortable at speed and know the track. It doesn't take long for an over zealous driver to find themselves off course and well anything can happen then..

I know how ESP works, but read the second paragraph in my post above https://mbworld.org/forums/4348402-post28.html "The manual says when you switch off ESP the "ETS will still apply brakes to the spinning wheel" and "the ESP operates while you are braking."

My question was not about the ESP light coming on when hitting the brakes, it was about ESP coming on when hitting the brakes when you've turned ESP off.

You did say "as far as the ESP button is concerned once you have it off and the little triangle is lit on the dash, it stays OFF until you hit the button again." So to answer my question, that means if you've turned it off, and it comes back on when braking, it will then return to no ESP on after braking, right? In other words, it only comes on as you're braking. That was all my question was when I asked: "If the button is off, does it go back to off after you release the brake pedal?"

Anyway, the whole point of this (for me) is that the nannies are there even when the button is turned off; it's not a 100% "nanny off" sort of button.....