I'd save the money and have a shop port your cylinder for your specific needs.
It is not simple to do. Plan on 4+ hours hunched over your cylinder, then you have to bore it anyways.
Chances are a shop would give you a break on the port, bore, and hone job. After you get your cylinder back from who ever ported it make sure you map their port job before you put it on the quad. That way if you like the porting they did you can always copy it and do your own custom port job. Having the right port, carb, pipe combo (For the terrain and how you ride) is way more important than some radical port job. I do have to say, my dad bought one of theese kits and it is well put together; but more useful for beginners who wouldn't/shouldn't attempt a DIY port job.