I saw some videos on youtube, of people making short exhaust from their original ones. I did it myself on my k5 750. I was very impressed by result, it sounds way better and louder, with no negative results so far.
I filmed my GSXR without exhaust, with exhaust and I did little video, as noob to noobs how to make it.
Drive by without exhaust:
How I did "shorty" exhaust:
How does it sounds:
I don't know if it is interesting to someone, I just thought to share :}