you will use all the factory connectors, and the wires attached to them. the only splicing comes as a soldered connection to above kit. it includes relays fuse block and obdII port. you probably could put this stuff together with off the shelf parts, and spend $50 and a bunch more time. i think i will buy the above. here is a how to to modify your harness.
http://www.lt1swap.com/2000harness.htm