I can't recall the article I read years ago ...or dreamed about but indeed there was no engineering there. It was stated that in theory you will achieve better fuel consumption with a lower suspension but how much for how low ... nada. I was hoping for a 3-5% but probably if you go downhill.Hi
In theory lowering car will reduce frontal area to increase efficiency through the air, but any reduction in fuel usage would probably be unmeasurable.
Plus if you actually intend lowering your car the Eibach springs are probably the way to go, as shown by Mal above.
For now I will keep the standard suspension and wait for my first shock absorber to leak or loose it's function and then I might go for the sport one.
I still have an 18 yo MK3 2.2 Tdci with OEM sport suspension and I was very happy with it, I just returned from a ride ... trying to compare it with MK5. From habit I like more the lowered position in MK3, the feedback and the way car is sliding in corners. As a parenthesis, for the same approximative speeds and driving style I got 7.7 on MK3 and 8.5 l/100km on MK5
Maybe you can give some more reasons why choose Eibach and not OEM.