A 190 will fit the rear rim and I'm pretty sure it'll clear everything, as long as you don't have a hugger. (Seems someone here has gone that route.) Go out and check to see if you can add 5mm to both sides of your current tire to be sure.
A 190 will make the bike harder to lean, especially quick transitions from side to side. The only benefit to a 190 is bling factor... unless your B12 is cranking out >150 ponies at the rubber donut.
The price doesn't look all THAT spectacular - at least compared to what you can buy other brands for in the normal 120/180 combo. I paid <$200/set for my last two sets... including shipping. (First set was a B'stone BT010/020 combo, second set was Michelin Pilot Roads.)