The valve in the midpipe on the gsxr1000's is controlled by the computer. It has a servo under the right rear of the tank on the frame. It has two cables attached, one to open, and one to close.
It's purpose was to make bottom end power more manageable, hence helping keep the front down under hard acceleration.
My old 02 1000 would ride a perfect 1st, 2nd gear 45mph wheelie when it was stock. After a full Yoshimura, it was so much harder to ride them that slow. The power came on so much harder, which I liked.
To each there own, but it seems like alot of work for something that will not give you a real performance gain.