I understand manufacturers very well, they will sell a car as much as the market can stomach and do it by cutting as much corners as they can on the features and service. Competition exists to ensure manufacturers compete to improve their product and service, no competition, they could legally sell you a painted turd and you would buy it up like its the greatest thing since sliced bread.
Tuning has always been conservative due to fuel quality, thats why after visiting a workshop tuner there is an instant 50hp gain. It takes 30 mins tops on the dyno for an experienced tuner, maybe less. Have you ever been to Nevada or Arizona in the middle of summer?
The Camaro and Commodore share the same zeta architecture, why does the Camaro get one and the Commodore doesnt despite paying more for less? Its effectively the same car underneath, its likely to be a $5 part tops