Looks better with a short barrel, in my opinion. Here is mine, all stock internals minus the 6.01mm Ra-Tech tightbore and King Arms hopup. The cocking handle breaks pretty fast because it's made of pot metal. Broke for me after 500 rnds or so, but I knew it was going to happen so I had it on hand. Reading around ASC you'll find handy little tips like these. I'm still a n00b with my GBBR, so I can't tell you much aside from firsthand experience or reading stuff on the net.
Turok seems to be an expert at these things and I've read a lot of his guides, so maybe do a quick search and see what you can find. Hope that helps =]
EDIT: To haters: No, there is no backup sight, deal with it
