Regarding carb boring, I've got to side with David. Theres a good reason why I don't offer that service, theres too much going on in there! I've seen lots of examples of carb boring from name tuners and I've got to conclude that none of them should ever connect a carb to a machine tool.
Heres the typical pitfalls;
1) A margin of .7mm must be maintained between the sides of the slide and the bore. If the bore is bigger than the slide air will bypass the venturi and make the engine run lean.
2) The bore must be consistent straight through. Many tuners offer carb boring on carbs with non-removable needle jets so they only bore each side of the carb up to the venturi. Thats useless.
3) Deburring of the slide to bore interface is critical to smooth throttle operation. AKA Stuck Throttle!
4) Deburring and finishing of the pilet circuit outlet is also critical and the height of the outlet also limits the bore size.
5) If you've ever ridden a 250cc bike with a stuck throttle you'll gladly pop the $200 for an aftermarket carb because laying on your back all summer in a body cast is kinda itchy!