As I posted a few days ago, I picked up an M4 recently.
Today I sent out a money order to SOCOMguy for his full-length magazine tube (guess I should have kept one of the Benelli OEM tubes I got from Numrich several months ago, before I had an M4, instead of selling them on ebay! ).
Anyway...I've been down this road before with other guns...and I know where it leads: It's going to lead to a lot of money spent, and a pretty kick-a$$ gun when all is said and done. I know that this magazine tube enhancement is like a hit of nicotine to somebody trying to stop smoking. First one puff (one modification), then a few more...and next thing you know, you simply dive in head-first.
Question about the collapsible stock: Why would a person want one? I don't mean this to be a flippant question. Seriously - what is the advantage, other than it looking more tactical? Does it reduce recoil? I doubt I'd ever want to shoot the M4 with the stock folded up (although I suppose one advantage of the stock is simply that you could, should you want to). And since I really only plan on shooting with the stock fully extended, I'd just as soon do so with the stock that comes with the gun.
If there is a compelling advantage to the collapsible stock, I'd be interested in one. But if its major advantage is simply looks, I don't think I'll bother.
And yes - it's true - I've never owned a tactical shotgun before. Perhaps there is a very logical advantage to the collapsible stock, and me simply asking the question exposes my cluelessness.