less than a pound... its tiny on our bikes... The weight savings is not the point of the removal on ours, ye, its somewhat of a small added bonus, BUT, the weight savings is not a good enough reason to pull it all out IMO.
My buddies CBR 600rr literally lost about 5 lbs by taking his crap off.
i pulled my out just to clean up the look on the bike. easy to do, if you dont wanna take out your rear shock to take it all the way out u can get in there with a pair of pliers and get the 2 allen bolts out, its not on very tight.