The other line goes to the radiator in my '88. The coolant lines that run to the throttle body can be bypassed, as they are there to prevent throttle icing in cold weather.
I would look into an aftermarket harness as well. I have had good luck with Robert at
www.fuelinjectionconnection.com . Their TBI harness was top notch, and pretty inexpensive to boot. Robert was really good about answering questions to get me going in the right direction, too.
For polishing and the runners, I polished a TPI for an '85 Trans Am I had years ago, but switched out the Torx for polished hex bolts, and painted the tops of the runners (where it bolts to the plenum and base) body color. It looked really sharp, and saved a ton of time polishing.