About the performance question, you will probably lose a small amount of torque at the low end when the runners are removed. The butterflys are closed at lower rpms to utilize the longer runner length, which increases torque. The butterflys open at higher rpm giving the incoming air a shorter, more direct path into the engine for better breathing and more horsepower. By removing the butterflys, you are eliminating all the intake tuning that the Mitsu engineers designed into this engine. You may not notice any power loss with your butt dyno, but the engine will be making less torque in the lower rpm range. I'd love to see someone do a before & after dyno tests to see how much power is lost and where the losses occur in the power & torque curves.