Busa's never been known for having the best brakes in the business. Even the kaw comes with much superior brakes. This is especially true for the first gen's.
What pads are you using? Not sure, i bought them from a sponsor galfer somethign
Do you have steel lines? yes I believe Sonny replaced the lines
If those two things don't help, next step would be to change your master cylinder to a Brembo, which definitely will get you what you want. Early Bird even put a GSXR1000's MC on his bike, which is an awesome idea and serves the same purpose of increasing braking power.
Also, make sure your brakes are bled well and to use good brake fluid - there does seem to be a difference between cheap brake fluid and the good stuff.