hmm you recon? what about once the copper shim has worn out from taking the plug in and out so much, and the seal on the headbuton copper ring and plug is no longer as tight? i remember in my old days with the non turbos when a plug was old you could see some pressure being release near the plug (ie bubles poping out now and then, especially if the motor was new, or if the headbutton had worn out a bit where the copper washer contacts the headbutton).

also the advantages you could gain from using a non turbo plug (and getting more torque like you said) could be counteracted by using a longer header/or pipe combo when you use a turbo plug right?

and my final point; ay man it's called turbo plug! it's quicker bro! naturally! lol i put a "turbo" sticker on my hyundai accent, i swear man, 20% more powa!