Don't try a P3 plug in the engine, they are tapered a little different that the RB/Nova plugs. I know they are very closeto the same plugs but I have never really had problems with the RB plugs but I have had problems when trying to run the Novarossi plugs. I have found I like the way the #5 turbo plug works best in my engines. As for the LSN, I wouldn't say they like to be lean you just want to make sure the LSN is tuned so that your engine isn't loading up with fuel while it sits and idles. Once tuned good you should be able to let the car sit still for a good 5 seconds then pull the throttle and the car should accelerate well without having to clean out a bunch of extra fuel first.

Also, generally you don't want to see any air bubbles in your fuel lines as these will cause you a lot of tuning issues.