Having done a few from scratch turbo systems...
First of all, you can't buy even a center section for a turbo for only $300, let alone the whole unit. Maybe an exhaust housing for that price. A typical new turbo unit can be had for around $500 to $800 for a small engine. How can that price be for all that?
Where's the exhaust manifolds? I guess you're on your own for hooking up the exhaust to the turbine section. And, with V8's, it can get deep what with crossovers and slip fittings to allow for heat expansion. The only part shown is intake items. I do see a turbine inlet piece that I guess you can weld to your own made up exhaust system.
For a turbo, small intercooler, fittings, etc. there's something wrong with the $299 price. It's either a misprint, or...?
I can't see the back end of the turbo that well, but it seems to be sans wastegate. NOT GOOD. You need boost control, or the manifold pressure will go off the map. It doesn't look like a variable vane type either... where's the linkage?
Check out the seller's username on http://toolhaus.org
There's a lot of complaints. When buying on eBay, I always check them out thru toolhaus. It roots up all the dirt on an eBay user. And... after recent changes, 100% rating means nothing anymore. The bad stuff just drops off after a few weeks or months.