Nitrous and a blower are a great combination if done right. The best use for such a car is street/strip. A centrifugal blower, by nature, doesn't give much boost at low rpm, which is where the nitrous shines. It isn't much use (the nitrous) on the street due to traction issues (spinning the tires at 100mph can be scary). But it makes a huge difference on the track with sticky tires and a prepped surface.

If your car is a street strip machine, keep the boost where it is and use a 100hp shot at the track. Use water/meth injection and a cold plug. When I run the nitrous, I use 100 octane unleaded. I have used it with 93 octane w/o ill effect, but it makes me nervous. If it's a street machine, forget the nitrous and pulley up the blower to give max impeller rpm where your cam peaks.

Here is a dynograph of my car with a 100hp shot and 22psi. You can see where the nitrous comes in. That as not the final setup, I turn the nitrous on with a window switch at 3,500-4,000 depending on track conditions.

Rich