GHK AK's would be best to get from RA-tech if you REALLY want one. For max realism GBBR ftw, but don't expect it to shoot 10K bb's without maintenance/repairs.. let alone 1k of bb's.. Just have to treat it as a real weapon and clean it pretty much after every time you shoot it. And make sure to google the hell out of reviews/problems with it before you buy. But either way I'd love to see more GBBRs man..fun fun
I know a hell of alot about WA/G&P/INO/WE's but Im not a huge AK fan so GHK 74u's im not too sure about. Make yourself an account on gasguns.info
http://www.gasguns.info/forum/viewforum.php?f=28 and search like hell through there. You'll find what your looking for.