Like I said, if you want to do piecemeal, you can get a great deal. Me, personally, I don't want to futz with all that extra crap, I want something pre-assembled that requires little to no effort at all.
As a point of note, I bought an LS1 out of a TransAm WS6, aluminum block weighs much less than the LQ9 (LQ9 is beefier, steel, better for boosted setups).
LQ9 stock is rated at something like 345HP/380TQ, pretty sure the WS6 is 380HP/400TQ stock. I've seen at least one shop in TN that pulled just a nudge over 400 RWHP and 400 RWTQ out of a stock WS6 with no power add-ons at all...at the flywheel, those numbers would probably be closer to 430/430 or something.
Like I said, it's all in what you want. I'm not boosting, and I don't want to screw around with anything more than exhaust, a Z6 cam and springs to get into the 425HP/425TQ range and smoke the tires off most anything out there. You can screw around with your LQ9 and boost it later to catch up to me
Bottom line: I paid more for an assembled unit with more power and lighter weight that doesn't need any add-ons. You paid less for something you need to assemble with less power and more weight and can handle lots more add-ons.
Like I said, it's all in what you want. No single setup is perfect for everyone. You need to knowledgably sit down and decide what you want before you get it. I don't think it's wise for anybody who never deals with the GenIII setups to just go to the local junkyard and plop down $2k on something only to realize there was a much better option for their specific needs at nearly the same price.