It's something cool to tell people you have, but it doesn't do much. Unless you're in real competitive drag racing where .01 seconds can matter, it's a low-value mod. Costs more than the returns. But, you can get a tad more throttle response out of htem. I'd get a downpipe first though, or better yet the whole stage 0 package from Vishnu. 50 hp for a grand can't be ebat.