14/50 rear sprocket and chain rec.

Hi im ready to try something bigger to help with the swing arm wear.

I would like to try 14/50 I already have the aftermarket case cover.
It would be for a R setup wheels.

which one should I get? I want flashy blue
for the front any will do? suggestions.
also what chain to get 112 or 114?

Renthal twin ring
http://www.motosport.com/dirtbike/2010-yamaha-wr250r-dual-sport---RENTHAL-TWIN-RING-REAR-SPROCKET
Supersprox Stealth
http://www.motosport.com/dirtbike/Supersprox-Stealth-Rear-Sprocket

Thanks!