Slip-on to full system

Short answer - not sure you can buy just the collector and mid-pipe. Try Gregg Spears at Spears Racing - he may be able to hook you up:
http://www.r3-forums.com/forum/761-spears-racing/21961-welcome-spears-racing.html

Be aware that the slip on may not be compatible with the rest of the full system pipe, the slip on is shaped to fit up to the cat converter, where the full system would be catless. I found my full system exhaust muffler sitting in a different position then those with a slip on.

Thanks for the replies fellas looks like I might invest in a new full system down the track.