Check his website:
http://www.rb-designs.com
Call Ron if you want specifics..
Answers to your questions:
He can 'do yours' or you can 'buy his'. The advantage of buying one is that it would be a 4-vent AirStriker Keihin. This model carb looks just like the PWK you have...except for the extra hoses (you can see a pic of one on my bike in the gallery). On the intake throat of the AS carb there are little 'wings' that focus or improve the signal to the jet block.
And...you could always then sell your PWK or keep it as a spare.
What does he do: The carb is bored to 36mm. A divider plate is placed on the reed side of the carb. It snugs up against the slide on the inside of the carb. Think of your carb now as a 2BBL (two barrel) carb. Velocity of the incoming charge is important. Velocity is improved when you have the same amount of air going through a physically smaller space. So...'barrel 1' is when the slide is below the divider and 'barrel 2' opens up when the slide is pulled past the divider. There are air rarification (smoothness) things that take place, too, due to the lessening of turbulence of the incoming charge dumping past the slide. (None of that is from Ron...it's my own understanding of some basic carb stuff...call it BS if you like...fine with me) He will cut your slide to a 7(mm cutaway) from the 5 it is now. You can purchase a slide from him if you want to keep yours as a spare or somesuch.
In addition to boring the carb and setting the divider, the pilot circuit is changed...casting cleanup/flow improvements. His mod does NOT 'come with' his finger adjustable air screw. If you want one'a them, make sure he knows it...and add $20 to the deal.
If you buy and AirStriker, it will come with the jet block height modified to match your PWK. That way needle/jet settings correlate better one carb to the other. You won't have to 'convert' your (oem) AirStriker setting to try to match some other PWK reference.
Performance-wise: Better off-idle response...smoother throttle response up through the mid-throttle range. If you have a 220, expect a good bit of hi-rev improvement...cuz the oem 220 carb is only 33mm.
$165.
Jump: Yes.
Fender: Yes. (that's a lie...but what the heck!)
Send it in clean. No hoses. If you get the AirStriker you will have to either use your PWK cap (angled entry tube on the cap) or buy another with the radiused cable tube.
Tell him where you ride (environs..temps, elevation, type of riding and such) and he will send it back to you real close jet-wise. If you ride at higher el. and ride a 220, consider sending your head in at the same time. Specify what kind of fuel you will be using and he will optimize your head for that fuel.
How's that?
It's a reasonable investment in your bike. If you ride WOT all the time on your 200, then it won't make a huge difference (bottom end response and mid-throttle smoothness being important points). If you ride a 220 in the woods, you're going to be impressed!!
***edit*** You guys are too fast...or I type too slow....I was the only one here when I started!