I recently fell in love with Sig's p320c in 9mm, and despite my own prayers to the church of Google, still have a couple newbie questions (previous searches on my own reviled incomplete and/or conflicting information). Any help is greatly appreciated.

~Is the only practical difference between the p250c and the p320c that the 250 is hammer fired while the 320 is striker fired?

~Will the p320c generally fit into most or all p250c holsters? (I notice the p320c comes with a factory p250f holster)? I was shopping for a shoulder rig yesterday and practically nobody lists the p320 as available for their shoulder rig, but most list the p250. If I order a rig for p250 is it reasonable to anticipate that it will fit my p320?

~Are there magazines with greater than 15rnds available for the p320c? I don't think I'm looking for, say, a 30rnd HappyMag, but a +2 after market magazine base plate would be great.

Thanks in advance for any help you can offer :)