I have a Mimi-30. It's no tackdriver but it's good for the intended job. Mine's a ranch version. Sorry, can't help you on the sights. Hi-caps are still avalible for about $12-$18 depending on where you get them. USA mags seem to work pretty good, but sometimes you have to tweak the feed lips a little. I don't think shortening the barrel is advisable in an auto rifle, besides it would cost more than I'd care to put into one of these. For flash hiders, get yourself a Brownell's catalog. They sell several flash hider/front sight combos that replace the factory unit and are easy to install.
I put a low power scope on mine and the front sight made a shadow in the view. I got an Eagle flash hider and removed the front sight (2 small screws) to solve the problem and it looks good too.
