Friend of mine runs that turbo(Honda Civic), and he used some kind of very small and thin alloy radiator (180mm long x 40mm) mounted on the pipe that runs into the turbo for cooling. He had another one unused and i'm curious to know if there will be a benefit of this.
From what i see water flow comes from the water rail above exh collector, into the turbo, and exits in the water rad, is that correct?
I don't know if this make huge difference in lifespan of the turbo, but i have space in my engine bay, and will cost me minimum efforts to try it.

its called a turbo pre rad and the rs turbos use them mostly.

There is a guy on here running one and it just helps keep the turbo temp down.

it runs from the water rail through the prerad then into the turbo and out that way the turbo is getting cooler water

And i thought so......great, it will be done in few days....with my existing exhaust manifold, the coolant pipe to turbo, runs very close to the hot manifold....

Not sure I'd bother. A few degrees C of the water isn't going to make much difference and presumably the rad forms a constriction and so reduces flow. My understanding is that one of the most important benefits of water cooling is that you get a natural gravity feed with a hot turbo when the engine is switched off. A rad above the turbo is going to cool the water as it rises so reducing the gravity effect.

Hot water always stays up, colder down...so maybe not only gravity matters, but water movement is also important....

Think this is a language thing, 'gravity feed' in uk is used to refer to the natural flow of water in a circuit due to temperature differences. Garrett fitment guidence restricts orientation to ensure it takes place.

well all i know is its used alot in the ford seen and it works fine on the coupe on the forum

also doesnt matter about gravity fed etc when the system is pressurized and is pushed around.

The gravity feed is needed after the engine is turned off. Heat still conducts from the manifold but now there is no oil flow or pumped water. Without gravity fed water the oil residue can cook.

Correct

It's called heat/flow convection, you can run a turbo without water cooling but you need to leave the engine ticking over before switch off for a good while to 'cool' the bearings. Assuming the hoses are plumbed into the correct points the mini radiator in between will do nothing because the system is not fully pumped anyway.