Help with front springs lowering project.

Hi all, i have decided to lower the front end of my avant a shade to help bring it in line with the rear end but i'm in two minds which method is going to be the best option.
My quattro rear end is allready quite squat to be honest and i think most quattro avants etc are and its looks to be fine but the front front end could do with lowering.
As the dampers are in pretty good cond i would prefer to retain them , rather than go down the replacement damper/shock and spring route.
Given the wealth of info on this forum and guys that have tried many combo's i thought i'd get first hand insight to the info i need.
If i go with shorter springs, which are the best ones to go with , will they have similar spring rates as my current ones.
I dont really want to make the front end much firmer to be honest as i find it fine for my useage, but, want to loose a bit of rideheight.

If i do change the springs, will i have to get anything else adjusted on the front end to compensate for the lower rideheight?
will the geometry change on anything.

any help and advise would be greatly received.

rgds
rob

thanks for the reply, by the looks of things 15mm may not be enough.

rob