I've had to straighten out the fuel tank neck through the firewall problem more times than I care to remember, Dave.

Having been a club instructor for many, many years, I always try to get to the student pilot before they assemble their trainer. The reason is to discourage them from using those through the firewall tank installations and have them switch to what a real R/C'er knows to do - isolate the fuel tank completely from any and all solid parts of the model.

Fuel foaming is one of those things that ruins engines and engine makers' reputations unnecessarily. You have the right to disagree, that is for sure, but I know that you are dead wrong on this one. I have solved too many problems with "junk engines" by isolating the fuel tank to change my mind.