Even if you buy a complete kit, ready for assembly, you are going to run yourself ragged chasing down all the little bits and pieces you'll want to build it "your way." By building a car using donor parts that problem is only compounded. Its a buyer's market, and for what you'd spend on building one from used donor parts you can likely buy a complete kit made with all new, 0 mile, performance-grade, pre-fitted parts, and chop months off your build time. Granted, you gotta write that check all at once versus scrounging for parts over many months (though many kit makers will break their kits down into bite-sized chunks.)
One thing that may not have occurred to you, but when you are zooming along at a high rate of speed, you'll already be asking yourself "Did I tighten that bolt?" Do you want to also be asking yourself "Did the spindle I bought from Acme Salvage get cracked when the donor Mustang was hit by that freight train?"
