is your induction an open one or inclosed? if its an inclosed one you have and you want more noise then go for an open one. the only problem is, is that you will probly lose power due to heat soak. i have an open one on mine and have put a heat shield around it to try and stop it. not sure if its working but it looks and sounds mint. and when i had it on a rolling road according to that it was doing book figures so although it hadent gained any power, it hadnt lost any either.
if you already have an open piper cross kit on it then you probly have the same one as me (the one that is made from a foam). if so then you could try one of those metal mesh ones. they are suposed to give a nice thoaty sound although im not sure there would be that much of a difference to be honest.