Do these actualy do anything?

[JackTar]

http://cgi.ebay.com.au/Kawasaki-zx10r-smog-AIS-block-off-plates-zx14-z1000-zx6_W0QQitemZ200185515118QQihZ010QQcategoryZ35231Q QssPageNameZWDVWQQrdZ1QQcmdZViewItem

[maggot1300]

looks like Pair valve block off plates (well they're called that on the suzuki's) makes a big difference when you run aftermarket pipes etc (helps stop backfires et etc, most of the stuff he's listed)the plates though are not really needed as I just blocked the feeder pipe running from the airbox to the pair system with a marble, its a fuck load cheaper but if you want to pull the whole system then you would need some plates to neten it all up and fill the holes.
it might be a bit different on the kwakka but I cant see why it would be.

[Booster]

looks to serve the same purpose, new 08 busa blockoffs will look similar to the Kaw ones.