I put a Luke's Racing Big Bore Kit (98 mm 13.5:1 Wiseco
piston, 444CCs) in my 01, along with hot cams.
I did the hot cams
before the big bore kit, and it really made a difference...a little more down low, a boat load in the middle (with a bigger hit), and a lot more on top. Plus, it got to the rev limiter a whole lot quicker. When I went to the big bore kit, the revs slowed down a little, but the power boost was HUGE. So much off the bottom that first gear became useless till I went up a tooth on the counter shaft sprocket! Worth the money? As a stand alone mod just because, though I love the extra power, I'd have to say it's only worth the bank for a racer. If you have to refresh the piston and cylinder anyway (as I had to), then it really isn't much more money over the cost of stock parts, and damn right it's worth every penny!