I think if you're looking at a 4.0 and a 30, you're fine.What if the rest of your application is very strong? I know that if you have GPA or MCAT weakness it is a good idea, but what if you are strong in those other areas?
I think if you're looking at a 4.0 and a 30, you're fine.
If you're on the fence in either, you take whatever they tell you to take.
I think you look at all things as a means of tie-breaking. If you have a 4.0 and a 30...you don't need too many tie-breakers. If you have a 3.6 and a 28, you might start looking for other things.
Why not be a super gunner and have a great GPA, MCAT, and take the recommended courses?