Boot and bonnet
I think the sheet metal diff between the city pack and non-CP cars is somewhat over-rated.
Easy enough to remove things like electric windows, power steering metal bumpers, rear glass, big stock battery (i useclight weight Gel bats) and get a lighter weight result than the mon-city pac series two CSLs. Also get rid or the damn lid mounted tool kit and you save weight and wear on the fragile trunk lid structure.
Imho, this all adds up to a bigger savings than the alloy door skins and hinges.