I know this sounds negative but I think you'll be lucky to find 50kg to remove! + the amount of time and effort the seriously clever dudes at Wolfsburg spent on the 3L in the wind tunnel you may find it difficult to gleem much out of the aero short of fitting a boat tail! (although that would be a welcome increase on the trunk space issue!) the Undertray is a good idea
__________________
-----------------------------------------
good things come to those who wait, sh*t turns up pretty much instantly
twitter.com/bertchalmers