Again no.if you plan to O.C. go with the quad.
if you DONT plan to O.C. go with the DUAL. (as long as the dual is greater than 2.4ghz)
The overclocked duo will STILL be faster than a overclocked quad because of the cache of the duo and because nothing takes advantage of the quad; If you were finding negligible performance with your e8400 then something else was wrong.
You will get BETTER performance and stability out of the clocked higher duo than the quad and you may not even be able to get a good clock from the quad anyways.