Its actually the opposite in my opinon, The mainstream customers care more about capacity of the engine and horsepower more than performance number and weight especially in a SUV stand point
When you talk about performance, how many customers know what 'performance' really mean?? Most of them think 0-60, 1/4 miles and lateral g is the judge of all performance. How do you define performance to the customers?? How do typical customers know the advantage of a light weight car vs heavy a high horsepower car??
Weight reduction is not as easy as you think. There are many trade-off to reduce weight. Less sound insulation, less luxury stuff in the cars..etc People want SUV with luxury product. The only way they can reduce weight is from the engine and suspension component.
Let say there isl a light weight X5 with 300hp to compete with a Heavy Porsche Cayenne with 450hp, consider everything else equal. Same performance and same price tag. Which do you think 'rational' customers going to choose?
Now, Sport cars are entirely different. We are talking about high power luxury SUV. Lighter sport car is faster in the corners and carry much higher speed, as the result faster staight line momentum. (no need to Stop and go) Do you know anyone will drive a SUV like that except RC and me