RealGM

Should i trade R. Westbrook - T. Evans for K. Durant & C. Copeland, i've alrdy got D-Will-Collison-Bledsoe on PG and only T. Young at SF

Yes I'd do it. Especially since you've got DWill and Collison. Id' drop Copeland asap after the trade though and see what's good on the FA list.