the plug is a restrictor.. you do not want to remove that... if you do you need to replace it with another size.. the stock one is the best though.. I run a P5 Turbo also.. an 2050 pipe... a novarossi gold 6 turbo plug... not one problem.. the engine is so fast and reliable it's silly... I'd ditch the plug and try another... but, I have never heard of an engine firing up backwards after it was just running correctly