I read about your ecodriving rallys in
your other thread, where you remarked that the car has to be
stock, with no modifications. Do the rules allow grille (radiator) blocks or pumping tires to a higher pressure? Folding the passenger side mirror can still be regarded as "stock" while slightly improving frontal area. Also, is there a judge in the car with you during the drive to make sure you don't break laws? If not, there are a few techniques you could try (eg coasting in neutral, or even EO(ff)C) which may not be strictly illegal, but which the judges wouldn't allow.
LED daytime running lights would also slightly help by reducing your electrical load by ~150-200W. In Lithuania you are required to drive with your lights on 24h/365, correct?
Does your TDI have an intercooler? Adding one would lower your intake air temperatures, which should
increase efficiency.
When will you enter the Lupo in your EM garage?