I was hoping someone would bring this topic up.

I did this same thing a few weeks ago... During the process of setting my car up with a new MSD closed loop chip (stage 3, greens) I decided to try a set of light blues I had from a previous project. I was also told the car would over fuel but since I still have my greens I figured no big deal I can always swap them out again. Well to to my surprise after installing the light blues and resetting the CO the air/fuel is still pretty decent with readings in the 11.4-11.8 range at full (24psi) boost. So for now I'll leave them in, I like having the additional flow capacity.

Another for Stu's closed loop chip.