Hi
My long-term gigging headless bass in my avatar uses EMG CS & P5 pickups, together with their 3-band parametric eq. As a builder I have used EMGs a lot and from personal experience with projects I haven't noticed much difference in tone when using different timber, larger bodies, downsized bodies, chambered bodies etc. However, in my opinion these are noticeable when using passive systems. Particularly timbers used.
I've recently gone back to passive jazz basses and the sound improvement compared to the active bass has been quite noticeable to other band members.
If you decide to go active, just make sure you can bypass the circuit by means of a passive switch.
Don't forget - we all wanna see pics of this bass!!
Cheers
Ian