Can cheap hotend parts sourced from China actually produce good prints? TL;DR
Is it possible to build a hotend, using separate parts, sourced on eBay, from China, and still achieve a high quality print?

In my opinion, the E3D V6 hotend is rather expensive, at $/£70, especially to those building to a tight budget. Now, obviously/presumably, there is some quite rigorous QA and testing of the build, and they have to pay for their research costs and initial machining set ups and this is reflected in the high cost. Also, the expression, you get what you pay for, springs to mind.
However, I wondered if I sourced the individual parts from China, for a dollar apiece, that is to say the:

Throat (with Teflon lining)
Heating block
Heatsink
Nozzle
Pneumatic connector (PC4-05/PC4-M06)
Heater
Thermistor

could I too, end up with a hotend, that performs as well as, or even out performs, an E3D hotend, or am I living in cloud cuckoo land?
After all, let's not forget that most, if not, all of the parts used in a E3D hotend probably come from China anyway, these days, as most production facilites have moved from the US/EU to the cheaper manufacturing bases and machining shops, in SE Asia.
I have read so many times that people were experiencing extrusion problems, shoddy prints, etc, from their cheap printer, until they finally shelled out the cash and upgraded to a genuine E3D hotend. After that the prints were much improved. I have read this countless times, in blogs, threads, etc., so I presume that it is not possible.
I realise that if the parts are not finished correctly, and end up with burring on the inside of the throat, nozzle, etc., then the filament will not extrude correctly. See tbm0115's answer to How long is an extruder&#39;s/nozzle&#39;s life? However, assuming that the parts that I receive are machined, and finished, correctly then there should not be a problem, right?
Has anyone actually done this? Is tinkering with hotends a done thing? Does anyone have any good pointers and/or tips?
NOTE: This question is not really after opinionated answers, in order to stay within SE rules - although opinions are always welcome - but I just want to know if anyone has first hand (positive or negative) experience of this.
Hard to say for sure - my whole printer is cheap parts bought as a kit in China by a Chinese student who abandoned it in the US (I resurrected it after it was abandoned.) It includes all the parts you list, and I think we finally sorted out what the thermistor actually is so the temperatures are more accurate now.

It prints. 

Could it print better? - Probably, but at some point replacing all the various cheap parts starts to look foolish .vs. just build a new printer with better parts all around, leaving the original functional. I doubt I've ever met a "E3D V6" and I'd have to google it to see what sort of paragon of printing it's supposed to be. The only thing I'm actually considering replacing is the nozzle itself, partly because I'm just guessing what size it is (mostly based on the way it prints when set to various sizes.) I'm also contemplating adding some sort of insulation for the heater block, having squnched some aluminum foil around it as a first stop-gap.

Likewise, if your concern is with burrs, etc. a degree of fettling by you can sort that sort of thing out, if you know to do it and how to do it (i.e. you need to be somewhat mechanically ept.) But of course "parts from China" are not a monolithic entity - there are good parts and bad parts that both come from China - given the state of internet sales, you may well have (unknown to you) the choice of parts that passed quality control, parts that failed quality control, and parts that quality control never looked at (some of which might pass, some of which might fail), from the same production facility, available to you from various vendors at various price points. And then there are many different production facilities as well.

Production in the US or Europe is no magic bullet either - competing with imports on price is difficult, so one hopes that superior quality is on offer, but it may or may not actually be from a given vendor, or a given batch of parts.