Whenever people change pipes or intake systems to something more open, this question comes up. Some people make no ecu changes and the bikes continue running with no apparent problems mechanically.
The other part of the question rarely asked though is not do you have to, but rather should you look at changing your fuel management system. The answer to this is almost certainly yes. If the budget doesn't permit it right away, you probably won't do any permanent damage in the interim, but you're also not getting the most out of your new improvement. The closer you can get to the optimum air/fuel ratio, the better your bike will run. As people have pointed out in the past, fuel really is not just the gas we burn, but the gas and air that combine to make those neat little explosions inside the cylinders.
Everytime we allow the exhaust to exit quicker or allow more air to get in, we change that important optimum air/fuel ratio that allows our bikes to perform most efficiently, and yes most often we lean out the mixture. The correction is to then add more fuel.
My advice then, Add the PC111USB when it's available, or the FI2000R which is available, as soon as you can. You'll be better off for the investment.
a dyno run with the AF analyzer gathering data will tell the tale. I do know from experience that drag style pipes cause a rich condition in the midrange and the only way to tune it is to take fuel away and the FI 2000 will not take away only add. you will need some dyno time with AF readings and possibly a PC111.