PCIII USB will let you ajust the fuel air curve your self with out changing the stock fuel air map in the computer on the bike. You can also remove the PCIII and the mods if you were to sell the bike and it would be back to stock (how you got it from the factory). PCIII lets you adjust the fuel air mixture with out changing the stock computer settings. If you plan on keeping the bike and not changing the mods you can just remap the bikes computer but if you plan on selling or getting a new bike you can take the PC off the one bike and move it to the other if it is compatible with the new bike. I am running the PCIII USB on my K5 GSXR and I am able to hook my laptop up the bike and see all the fuel ratio's for tunning. I would recomend that you have it tunned by a certified Power Commander tunner once you down load the map that fits your mods from their web site.