What part do you need help with? IIRC, the '03 and below have a shrader valve on the fuel rail, you buy an adapter piece from somewhere, (summit being the only place I know of off-hand,) and screw it on to the valve, then screw the sending unit in to that. Route the sender wire through an existing grommet in the firewall and consider it done.
Your A/F gauge will require you to tap in to one of the wires of one of the o2 sensors (don't ask which one, I never installed one,) then run the wire up through somewhere (probably the firewall.)
In trying to keep the mods on my '04 somewhat reversible should I ever sell it, I used the fuse box to draw power for the gauges, ground the gauges, and hook the dimmer wires up to. Basically, run your 2 white wires from the bulbs together, then run that one wire down to fuse 37 (buy the little fuse tap things from autozone.) Then run the 2 black wires from the bulbs, and the 2 ground terminals in to one wire, and run that down to the fusebox where there is a screw you can back out, then put a ring terminal on and snug it back down. Lastly, run your 2 power terminals from each gauge in to one wire, and run it to a fusebox position that is 12v ignition on (such as the radio.)
Good luck.
