No matter what the pipe vendors say, if you really want to get the most out of your aftermarket exhaust, you’ll want to invest in some dyno time to have a custom map created for your motorcycle’s particular fueling needs. Of course, if your bike’s EFI can’t be refreshed, you’re looking at adding an aftermarket control unit from a company like Power Commander or Bazzaz. The good news is that you’ll get the most power out of your bike’s engine, and you’ll be able to minimize any undesirable valleys in the curves as well.

Note: This type of modification is illegal in some areas. This should go without saying, but if your bike has carburetors, then EFI tuning doesn’t apply (but you knew that, right?) A jet kit is what you should be looking for.