My 18th birthday is coming up, and I'm deciding what to gift myself. I can't consider myself a republican unless I own some sort of Gun, that will in time be modded to all ends of the earth. I can't decide which. I love the compactness and all the ways you can customize an MP5, but then again the AR15 is just awesome, and is so customizable. So until I can get a license to modify a lower receiver, it will be a semi auto. Any thoughts?