You get what you pay for. These bodies are less than half the price of a square body blank.
Hopefully he will chime in, but recently i assembled a guitar for a forum member assembled from an 'bolt-on style' epiphone LP body, and an ebay neck. The neck was so cheap, he bought two. The first one was slightly warped, but we suggested we might be able to fix it with a level. We couldnt, because ALL the frets were loose. So, we fixed those, then we fret levelled, and all the finish started FALLING off the neck. We called, and he informed us there was a second neck... ok, lets have it! The second one had a hump in the neck as well, but we managed to fret level it out (plus reset five frets!), at the expense of fret life. We didnt charge for the first neck, because we felt sorry for the guy. In the end he still spent more than a Warmoth neck, and he knows his neck is prone to warping and is only a matter of time before it needs to be replaced.
I have a lot of people bring these cheap ebay and AMS necks to me. There are just too many (more than half) that are simply not usable unless you can accept the lowest quality and very bad playability. To fret level, and replace the nut, will be the best part of $200, plus the original cost of the neck... puts these at more than a high quality Warmoth.
As for the bodies, ive seen a heap of those too. The timbers are not dried properly, so a lot are cupped slightly when they arrive. Ive seen bodies split on the glue joins. Ive seen holes patched up and redrilled. Ive seen bridge holes that dont position the bridge to suit standard Fender scale lengths. Ive seen tele control cavities that are too big for standard tele control plates. Ive seen strat routs that arent deep enough to allow you to lower the pickups (so they just hit the strings), and ive seen them rout too deep so the rear trem cavity and the pickup cavities are just a half millimeter away from being a WINDOW! The timbers used can only be described as driftwood.
Buyer beware.
Im sure SOMEONE got a great cheap chinese neck or body off ebay, but we have NEVER seen one. Your time and effort in building up a project is worth more that these products will allow.