Where did you hear that the stock Align ESc internal BEC is okay for a 4S setup? I would disagree, based upon my own experiments and other people's postings. I have a SportBEC that I used when I was experimenting with 4S. I would definitely invest in one. Other than that, your setup looks good. Use the HS calc at www.ReadyHeli.com to try out different pinions on a 4S setup to achieve the HS you want. Unless you're going for radical 3D and using CF blades, I would shoot for around 3K RPM.