i have that second pipe (though i haven't ran it yet). i've done my homework and apparently it's a great pipe for high revving applications on a kitted bike. it wouldn't be worth the money on a stock bike, though. if you're not going all out, i would go with a circuit style pipe. best all around performance from my experience.
what are your future plans for the bike?
the chrome one that cory has on his ciao (available from treats) is a really great all around pipe for the price.