Got a bit of rust on my M5 bootlid which will be a pain ro resolve so thinking of changing bootlid altogether

Looking at my options i noticed there is a US spec bootlid available if i can get hold of one. So thinking it maybe a subtle mod without going over the top. Wot do ppl think about this and wot are the legal issues with it if any as doubt i would be able to run UK spec plates ???? My number plate is only 6 digits but could i run US spec plates ???
US spec
UK spec