Exactly. If you want to get the full benefit of larger intake pipes, you would need larger throttle bodies.

Apologies sarcasm doesn't relay in text well. No that's not how it works. Larger diameter intakes can and do make more power than smaller ones on the same size throttle body. Not that I'm saying a 5" intake would on the Z. There is a point of diminishing returns, not that I know what that point is on the Z.