PSU for mini-itx case?

[Ansem1]

Hi everyone!
I want to build a mini-itx pc and I was thinking about the fractal design nano S as a case.
From the spec the max length for the PSU is 160cm.
Can yousuggest me the best psu that can fit in it? I want it to be at least gold, better if platinum/titanium if the price is not too high. I want it to be as silent as possible too.
I was thinking about those 550W:
- Seasonic prime ultra platinum -> 115€
- be quiet straight power 11 -> 100€
- EVGA Supernova G3 ->100€
- Corsair RM550x ->85€

I put in bold my main choises.

As I said, the noise is the most important thing. I will use it with a ryzen 1700 and a gtx 970. Later this year I plan to upgrade to AMD navi. Still since I will have only 1 GPU I think 550W will be enough.
The price is not really a problem since I plan to keep it for nearly 10 years like my corsair HX750 that I have now.

[Stefan Payne]

Bitfenix Formula.
Or maybe Cooler Master V-Series

You want to look for something with 140mm length if possible.

The new Silverstone GS Series seems decent as well, though the fan is an issue...

[Ansem1]

How does the CM V-series compare to Seasonic prime Platinum?
Also, if I went for a mini-itx I would need an SFX PSU. Other than the Corsair SF600, there is some other good SFX PSU?

[Spectre]

I just went the mini-ITX route and I ended up using an SFX-L power supply. There are some good options in the SFX-L realm.

[Ansem1]

Not sure what's the difference between SFX and SFX-L.
BTW I'm looking for a normal SFX, so I was thinking about the corsair SF600 platinum.

[Jon Gerow]

Not sure what's the difference between SFX and SFX-L.
BTW I'm looking for a normal SFX, so I was thinking about the corsair SF600 platinum.

SFX is 125 x 100 x 63.5mm.

SFX-L is 125 x 130 x 63.5mm.

They both fit into the same SFX "cut out", but some cases may not have the depth available to install the larger SFX-L.