I will warn you that the TBR pipe is loud, very loud. If you do decide to spend the money please get ear plugs.
Please take a look at the dyno charts from my bike, the AreaP system makes a huge difference (fyi the blue is a TBR slip on). There is 5hp gain at peak and 12hp gain at the soft limiter. Does it make it feel like a liter bike, no, but does it give it a little bit more power and pep... heck yes, I love riding my bike even more after getting a full system.
http://www.ninjette.org/forums/showp...18&postcount=3
$415 is a ton of money to spend on a slip on imo. If you are getting in that price range you should just go with an Akrapovic if you want a slip on that badly. If it was me, I would just save up and get the AP full system (it's $495 for the standard CF system).
http://www.biohazardcycles.com/servl...-CARBON/Detail