I'm thinking that it would be pretty cool to have a shorty AK, but I don't have the dough to buy a complete SBR right now. Instead, I'm considering either getting a Krinkov-style shorty kit and assembling it into a registered SBR down the road, or else getting a completed AK "pistol" now, and getting a tax stamp and stock later on. Any thoughts on which would be the better way to go? Is there any real difference between an SBR and pistol other than the rear trunnion?