What can I expect going from my stock size reartire 190/55 to 190/50? Better handling? Does it change your speedometer? This is my second post on this I know, can anyone explain??

 

Well, the stock size is the 190/50, so you've got it backwards there. If you go to the 190/55, the turn in will be a little easier and feel as though it's more nimble. Slightly different profile, so it'll make handling feel more precise. It'll seem a little twitchy to best describe it.
On the bad side, it'll throw off your speedo just a little...and the odometer, but not a huge deal.