The Haltech has about 10 extra inputs and outputs that can be programmed to do anything you want.
As for wiring it to the chassis, all you need is a ground, constant 12V (25amps) and 'hot-during-crank' ignition wire and a connection to the electric fuel pump. Everything else is connected between the engine and ECU. It is a very simple system with only a few sensors to make it work.
Haltech Platinum Sport 2000 with flying lead harness (about $2000.00 cdn)
HT020002 Dual Channel Ignition Ignitor (about $175.00 cdn)
Wideband O2 Sensor with controller (about $250.00 cdn)
2 of 1999 model 3.1 liter V6 throttle bodies (used about $50.00 cdn)
Coolant Sensor, Air Temperature Sensor, 1 extra Idle Air Control from the 3.1 V6