A turbo car is really a different beast. With reasonably sized turbos it does not need get up to high rpms before it starts pulling. There is so much low end torque. My car for example (which is pretty tame by turbo standards) is making more than 400 ft-lb of rwtq at 2700 rpm. I could not even get it to stop slipping the tires when it was strapped down to the dyno, much less the street. Bottom line is you go with higher numerical gears for torque multiplication. With a turbo setup, you don't need to multiply torque-it is already there. Also as you mentioned, the turbo responds to engine load so the low numerical gears will do that.
On a centrifugal blower or NA car, it is a different story-you are trying to get the car into its powerband as quick as possible.
97 Laser Red GT-248A Wingless model, Built Lincoln Mark VIII motor-Procharger D1SC, 3 core IC
2012 Black GT-Saddle, 3.73s, Brembos, Shaker1000