Lewis,
I met you, and you are a very cool guy. You took a road that only a few have taken. Some are set in thier ways, so be it. Mike says in that last quote, "You simply can NOT argue cubic inches... The more you pressurize that little four banger to get that power, the closer to the end of the engines life you come." I don't care who you are, this is true. You may have a wieght advantage, you may get good miles per gallon of fuel (if you're good with the GO pedal), but don't feel that everyone is against you. Don't feel that you have to justify your decision for your engine choice. You may have to rebuild the engine sooner than others, but this is the engine you wanted for your Z.
I have recieved a lot crap (mostly from purists) for putting in a V-6 in my Datsun, but for me, the ends justify the means and I could care less what anyone says about it. I built this vehicle for me and no one else.
Try your best to brush off what some guys with little knowledge have to say about your engine choice and drive your Z with a smile on your face knowing that it suits your needs and what you wanted. Live it up man, you have a quick Z that is on the road and you are enjoying it. That is more than some people can say on this forum.