See the only "junkyard" parts on my car is the manifold, turbo and bov.
Those are the most important parts of any turbo kit.
See you are getting home made, junkyard, and assembled kits confused. If you buy a Turbonetics T3, a revhard manifold, AEM EMS, greddy BOV, Tial wastegate, spearco intercooler and piping all new it's not home made. Junkyard is junkyard, self explanitory. Buying hard parts from vendors is not "preassembled" either. I have raced most of my life and I have had a boosted car longer than 99% of the people on this board and I have yet to see a fast junkyard turbo car (meaning non turbo car from factory made to be turbocharged with junkyard parts). And by fast I mean mid 13's or lower.