Don't worry about it running lean, the snorkel and exhaust make very little change to the air/fuel ratio.
I'd worry if there is a dna stage 2 filter, then you'd need a fuel commander.
Kev's fuel mod is a very good affordable alternative to the power commander.

I don't think you can adjust these motors by feel very well.
You won't feel the difference between a bit lean and very lean.
But again, with your setup i wouldn't worry about that.

Are you planning to mod the bike in the future?
In that case i would save for a power commander.
If not, Kev's fuel mod will be perfectly fine for a bike with simple airbox mods and it will provide you with a smoother ride with a slightly increased throttle response.