Be carefull about comparing 60' times, a car with overhang will have a lower time then a straight up car because the car with overhang is 24" further that the start beams thus the time is based on 58' and not 60'. Other racers times don't mean a toot as long as I can hit my index. My car on 33x12x15 GY on a 10" rim(tubeless) with a 3.90 gear runs a 1.09-.10 60' without overhang, ands hits the 7.0 index. Tire compound only comes into play if you get new tires frequently, if not all compounds equalize after time due to runs/heat cycles, sun light, age. I can say that because by the time I get new tires, they don't have that compound in stock or they changed/discontinued it., put those on, car runs the same.