macbook pro 2.3 vs 2.6 for logic?

Hi guys

I am looking to buy a macbook pro which i will be running logic pro on, and im stuck between spending the extra on the 2.6 vs the 2.3.

I'll be maxing out ram on either one of them, but the 2.3 is stuck with the 512mb vram vs the 1024mb on the 2.6 - will that make much of a difference for logic pro? I'll be using two external displays with the system too.