I used to think that, until I put R compounds on my (then) stock suspension car. When I gained four seconds on the Willow Springs big track, I rethought my strategy.What's the point of R compund tires if the car is rolling on the door handles to begin with.
Sure, it's nice to have a car that's composed and all that (I have that now), but even back when it was stock - scraping on door handles as we proverbially put it - I could still keep up, and in some cases, pass "faster" cars that couldn't hold the line due to poor tire choice.
Grant - it's your money, so do as you please. The simple fact is, even with a good setup and bad tires, you ain't gonna get the results you want. I guess the ultimate year-to-year lesson is, $$$ = speed. Our fathers and grandfathers ran into similar paradigms ever since the automobile was invented