Not sure I'd trust something like that. Don't they use them to trick the auto choke into thinking it's colder and thus use more fuel?

A lighter foot really is the only way I'm afraid.

I run the A6 2.8 quattro on the left there and regularly get 32 - 33 mpg. More if cruising the M-way.

And I don't drive like a granny - not yet anyway.

Smoothness is the key...