OP - I propose you attempt the layout install yourself. I say that because it will help you troubleshoot and self-support the system in the future. Leave the wiring and tune to a shop and save labor costs on the bottle, lines, solenoid setup.
Also I am a big proponent of progressive controllers. Your typical nitrous dyno result shows a huge spike in wtq when the n2o comes in then tapers off fairly quick as rpm climb. PC ramping options allow you to smooth that torque spike out somewhat. I personally have always been hyperfocused on managing wtq rather than computed derivative whp. Of course if you are drag racing maybe you want the torque early in the first 60'. Balance between safety & performance. Setting your rpm window to 4000-7000 is a good place to start.
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