In all honesty Blindaussie? Not a lot . Do you know what is the best performance increase per price I found? Taking the rubber seal off the airbox as advised by Dazzco some year or so ago.
I shall relate a story I posted on another forum that is never to be mentioned here for fear of the men in black turning up on my doorstep with the flashy thing ,joke mods ok joking.
Anyway , I took the rubber seal off my airfilter just to see if I noticed anythng one day and like all these things didnt really feel anything. My brother has a TBird , same spec same pipes high flow filter BB kit but the slower version in Black not the Blue with cream.
So we ride for a few months doing the usual hack it from time to time . Burning from lights ect all the totaly irrisponcible things "they" tell the non riders of the world about. Anyhow to the point. I always beat my brother off the line . I was always a bike lengh ahead of him . I could always catch him up if he opened up on the road.
Didnt really think much of it until I remembered and he moaned . The rubber seal on the air filter was the only thing that was different. So I took his off and we went for a ride. I can still beat him off the line most of the time because im faster with the clutch. I cant gain on him when he opens up and if he opens a gap I cant close it.
That says to me the rubber seal gives you a bit extra for absolutly nothing.
The air filter. Hey it costs nothing really so what has anyone got to lose and with the TORs why wouldnt you free the air flow a bit?
I got a KN speedmaster high flow airfilter and it cost , £30 or something. It is slightly too long but with a bit of messing (about 5 seconds of messing) it fits.