Your arguing about something you have 0 first hand expierience with. Basically your talking out of your ass. My brother and I just finished putting a T3/T4 turbo setup on his NA block this summer, runs great at 12psi and pump gas. From what the Z31 community has examined the NA pistons are every bit as strong or stronger then the turbos. Even Nissan knew their 7.8:1 was too low, which is why it was raised to 8.3:1 in 1988, and 8.5:1 with the Z32. You can babble all you want, but its been proven time and time again its a reliable route for making power.