My son and I completely rewired my 83 GP -- took out all the original wiring and put in a Painless "18-Circuit Universal GM Keyed Steering Column Wiring Harness" (#10201). We also completely re-wired my son's 73 Camaro with a similar system. I won't go into "this is better than that" -- just stating what I did. The Painless harness has all wires nicely labeled along the full length of each wire and the colour codes match (for the most part) the original GM colours. This makes it easy to reference the original GM service manual. We were satisfied with the quality of the harness. One area that, in my opinion, needs improvement is the Installation Manual. Also, cost is on the high side, but is comparable to other manufacturers.
The only reason we went with a kit rather than making our own harness is that the wires are all labeled and numbered. This makes it much easier to troubleshoot down the road. Also, some of the odd GM colours are hard to get. BTW -- both cars started on the first try! We were happy campers
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This is not an endorsement of the product -- just stating my experience. It's up to the OP to make up his own mind. Good luck!