Theres alot of modification required, Looking for DIY atm.
EDIT: Found
Wiring:
Source:
http://honda-tech.com/showthread.php?t=1053318 via Google.
Physical Mounting:
Couldn't find a DIY for this, You will have to make custom mounting for this to sit where you cluster sat.
The source for the Wiring article shows how to make custom mounting to mount a DC Cluster into a EG.
Use same logic and steps to make the mounts for the 99-00Si Cluster.
Good luck, if you do go on this path post pics and make a DIY article here.