Depending what options you'd be getting on the '13 it could be worth it. I had a stripped '11 (literally no options outside of interior trim) and traded it for a '13 with ZCP, Nav, and a few other options.
Would you be trading for essentially the same car or would the '13 be different?
E92 M3 | Melbourne Red | ZCP | Nav | 6MT | CF Roof
Blue-Gray Aluminum Trim | Ventureshield