IMHO a built auto will always be quicker than a clutch operated manual, on the strip, street or circuit.
Plus Nitrous is easier!
You must run the nitrous on a micro switch, as there is no metering of it, so it will be providing too much nitrous and fuel at lower load and can nitrous backfire (very bad!). If you watch the Nitrous 10.5 cars in the states, you hear them "boom" the nitrous on the start line, after they purge. Basicly they are turning on the nitrous, at 3000rpm, and you hear the note change, and the revs shoot up a couple thousand RPM, pretty cool, but has to be done right.