Will be interested to see if anyone has actually tried a kit like that. It's certainly cheap!
I just bought silicone coolant & boost hoses from Pegasus Racing in Wisconsin for a custom 1.8 liter turbo install in my old Scirocco track car. It's crazy expensive stuff - couplers and elbows run $15 - $30 each, so total cost adds up fast. Here's the link to their cooling hoses:
https://www.pegasusautoracing.com/advcat.asp?CategoryID=3COOLHOSESIZE
Had to do that because "normal" hoses won't fit (sure wish they did - would have saved a lot of money).
One thing I did notice - the ebay kit appears to be using regular cheap hose clamps versus a full circle "lined" type which better protects the hose:
https://www.pegasusautoracing.com/productselection.asp?Product=3613
But I've just got to ask - why do you want to install a kit like that, anyway? Regular OEM coolant hoses have advanced to the point of often lasting the life of the car. Wouldn't be surprised if you can run OEM hoses for 200,000 miles, so even if I ever DID have a hose fail, I'd just get a known brand name from any local auto supply store. That way I wouldn't have to worry about a part of unknown quality that I got on ebay blowing up at the worst possible time.
If you want to spend money on your car - direct it toward something that either makes you go faster or improves reliability. That said, those VW/Audi plastic "flex" hoses (PCV, Aux Air, etc) are complete junk - you can crack an old one by just looking at it the wrong way!! Anyway - just my 2 cents ....
Regards ..... Fred