I'm running STD airbox. I've had trouble running pods before but admittedly not with an injection bike, only on carbs.
I'm now running a Wide Band O2 Commander with the pcv. That could help if one did go down the pods route....
Got 97.8 before the WB2, which probably won't add any top end power but has made the low down, small throttle oppenenings much smoother and stronger. Feels just about right. Not sure I need any more power and the weight saving has made a massive difference. Very happy with it. I'd say the engine has lots of charecter...
I think both tsr air box mods and a cat free pipe will see you just shy of 100bhp at the rear wheel. Nobody's getting any higher than that. That's loads. With weight off the bike it feels fast and lively. Like you say it would have to be cams next, if you wanted to take it further. That would, I'm guessing, loose you some of the flexibility and low down power.
I've got a Versys 1000 as well. No doubt faster than the CB but it doesn't feel it. The number go up quickly but it doesn't feel as good.
Maybe new cams would change that charecter, depends what your after I suppose. I'm interested to see what it would put out tho ;-) someone got to do it soon..... anyone?