I've been wanting a semi-auto shotgun for a while now and I've eyed the 930 SPX. Yesterday, I went to my local gun store and they are a authorized Benelli dealer. I was checking out the M4 and when it comes to fit & finish it is far better than a 930 SPX. They're asking price is $1,799 and I was very very close to buying it, but I wanted to know a few things before I decide to spend a good amount of $ on one. How many different models are there? I know about the new H2O, Camo, & standard black (which I really like). How about barrel size? Is there only a 18.5 inch? Are there any common problems with this shotgun? I really wanted another 1911, but I already have 1 and another hand gun so I'm thinking a Shotgun should be my next buy. The M4 is a very expensive shotgun and I need to know these things before I jump into this purchase. What is the warranty on these and where can I get accessories?