You do not need an ignition module to use a PC3. A PC3 controls the fuel injectors, so that you can optimize your A/F ratio. It is usually used when you change something like your intake or exhaust, to flow more air. The additional air can require more fuel to be added to maintain an optimal A/F ratio. SOME bikes can see a small improvement when stock, but my experience has been that it is not necessary for most modern stock street bikes - especially new ones that have better mapping from the factory.