Both the emission systems used on the EXC are downstream of the ECU with no feed back. The air injector lets more air into the exhaust, essentially a huge exhaust leak that adds to the volume of gas coming out the exhaust. More volume means the percentage of pollutants coming out the exhaust is lower. But, you still get the same amount of pollutants weather this this device is hooked up or not. The charcoal canister and gas tank capture system actually reduce the VOC being put into the air. It captures the fumes coming off the gas tank (and off the carb on the 530's) and burns them in the engine. If you keep the bike upright, never overfill the tank and never park it in the sun when full, then this system will work OK. But, once raw fuel goes out the overflow pipe and gets trapped in this system, your engine will run erratically and may not run at all after a tip over. On the BMW's it would even lock up the motor. The ECU controls the venting from the charcoal canister into the intake with an electrical solenoid. The ECU does not know if this solenoid is even connected or not, there is no feedback. This system allows a little air to leak past the throttle body all the time, which makes the idle slightly higher. When you pull this system, you lower the air leak and need to make it up by raising the idle. The ECU can't tell where the air is coming from, through the TB or leaking in from the Evap system. The EXC and XC-W's have different MAP's, but they are very similar and labeled 'California Green Sticker' compliant. These are 'restricted' maps, they don't respond to the different MAP plugs, they don't allow modification with the User Setting Tool. You can replace the MAP's now with the un-restricted ones for 'off-road use only' or Australia, which is way, way off road. On a slightly different topic, KTM just got its pee-pee slapped and will no longer sell after-market slip-on mufflers for street legal bikes. They were a good source for Acropovitch and FMF exhaust systems, but the Fed's noticed this and shut them down. I think this was mostly due to the latest Kalifornia code about only allowing stock mufflers on 2013 bikes.