240 engine swaps?

[COLOR=gray] Hey every1, iv been thinking about what kind of car to get for my first, and after many differnt choices iv finally landed on the 240sx coupe. i dont really care if i get the s13 or s14 chassis, but preferably the s14 if i get enough money just because of the taillights. anyhow, iv been looking up all kinds of stuff on engine swaps and which would be the most efficient. the sr20det seems really good and reasonably priced, but i need to know if its illegal in the states? also...i know that some people have been putting skyline engines in 240's well...arnt they AWD? how could you set it up to be RWD without major work? i heard from a friend that you could take some things off and the part that spins the front wheels just spins...this sounds like the kid either made it up...or if its true...wouldnt you be losing power by having the front thing just spinning?? well anyway...no matter what i do to my car i need it to be able to drive on the street, not necissarily street legal, but if i did get a illegal engine in the us and drove it on the street how would i get away with smog? anyway...one of the other things i wanted to know is just how much work it is to swap a sr20det into a 240? is it worth doing it by myself or should i get a shop to do it? and if i do it myself, is there anything i would need to buy to install it besides the engine and transmission? ....well ...im done... and excuse my retardedness twords cars...im only 15 and trying to learn the most i can without actually owning one... any comments are helpful.. thanks

yeah....um....just let this one go down the list....

im serious guys.....