Agreed.

I just went through a similar process building a Surly Pacer. I started the build with a doner bike and collected parts until I had enough for assembly. While it did take some time, buying it a piece at a time allowed me to find NOS Shimano 105 5500 and Ultegra 6500 parts to complete the build. I found the parts significantly cheaper than even new Tiagra (The stock equipment on the Pacer) and Sora parts.

Now that it is all said and done, the bike has a better quality drivetrain than what comes stock. And, I did this for a little less than what a stock Surly Pacer retails for.