Please do not take offense, but I have to respectfully disagree with the opinion that the Street Rod Pearl will outhook the Thunderstruck Pearl in the backend. Both balls have the identical cover, the Reactor Pearl Reactive. Only the cores are different. I have thrown both the Thunderstruck Pearl, and Street Rod Pearl with identical drill patterns, and my Thunderstruck Pearl was slightly stronger than the Street Rod Pearl. Also, I was quite suprised by my reaction with the Street Rod Pearl. Even though it is a pearl ball, it gave me a more even roll than I was expecting. I would have expected slightly more skid, and a sharper move at the breakpoint with this core/cover combo. I have a good amount of hand(specs are in my profile), so that might account for the reaction. According to Storm's website, the Street Rod Pearl is for medium to light oil. However, with a lot of their "lower end" releases as of late, it is a bit stronger than they are advertising. Still a great piece for the price. Hope the information helps.