I have a Super Nova Tactical. It's a very well built shotgun, with lot's of aftermarket options. I've added an OEM Benelli 2-round extension, a GG&G flashlight mount (with an OLight PL2 Valkyrie attached), a Mesa Tactical top pic rail/side saddle, and an ATI Raven adjustable buttstock. Here's a pic. It's a great gun that's easier to maintain and much less finicky to disassemble/assemble than my Mossberg 500, but it's pretty heavy with all this stuff on it.

You can definitely change out the barrel later on if you want, but you'll probably have to get the barrel through Stoeger Canada, rather than just going down to Crappy Tire or Cabela's to pick one up.