That looks cool mate, get the "3818" looking a bit worn and it'll look authentic (sp)!
iirc im sure german units in ww2 only used 3 numbers on the tank to denote iirc squadron, troop and tank within troop
i would also consider a rc boat there alot cheaper than both the tank and plane http://www.wonderlandmodels.com/products/venom-king-shaves-c1-34-rtr-electric-boat/