it's not forbidden. some shops (
www.okaysoft.de for example ) have a special section for import games without a rating. you just have to prove you're 18+. ( irgendeine kenn-nummer von deinem personalausweis )
if you order at shrapnel's store, i think there's an option that they send it to you without the box ( 'büchersendung' sozusagen ) and you don't have to pay the extra taxes.