If you're just going to pull out the snorkles and maybe drill the bottom of the airbox and filter, you should be able to do it without rejetting. If it does go a little too lean with the drilling, you can just drop in a bit of pasteboard to block the holes untill you get the pipes. You won't see much of a power gain with the stock pipes though because you need to get more air out to make room for more to get in.
As for the Epco pipes, I got a set when the only alternative was about twice the price. They work well and sound nice. I think they are still probably the best value for the price.
