I
was determined to go this route as well for my 147. One trip to ACE Hardware and I came up with a total of about $30 just in my wire measurements. Now, the connectors you will need are going to have to be sourced all over the map, and you'll have to be able to buy them in 1's, 2's and 3's. A few will really take some scouring. I estimated the price of the connectors & shipping and then finding the correct harness cover....it just wasn't worth it.
Wound up buying one of the harnesses on Ebay from Porch Electric and so glad I did. What they sent me worked perfectly, and was correctly color-coded down to the proper lilac for the headlights.