Do most need one, nope. The stock tfi systems pretty damn capable for most combos. I wouldn't bother with one on any "real street car" still running on your typical 91-93 octane pump gas. Now a track toy or something built to rev it can be beneficial but a typical basic ignition box on a mild build is absolutely pointless if it doesn't have a timing control or a rev limiter. Spark wise its not going to make more power.