I use it once in a while when merging onto the highway.

It allows the engine to rev right up to 5,000 rpm and that helps blow out the carbon from your valves.........much better than a can Seafoam will ever do.

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I took mine down the race track 4 times im sure its cleared of carbon

 

I've been playing with my ECT button lately and I have noticed it does 2 things. It raises the shift point as you know but it also seems to increase the fluid pressure to the clutches which firms up the shift points....less clutch wear I bet but gears are a little grabbier....a good thing actually.
If you are easy on the pedal then the shift points don't seem to be that much different than with the button off. I just leave it on all the time.

 

I could tell a big difference when I would use this on my turbo when it was an auto and then I bought my 00 and can't really tell much of a difference at all. Maybe a little firmer on the shifts but that's all I can tell.

 

like ! ! !

 

mine is ALWAYS ON!!! ill be doin a-hundo on the freeway on 37s