Hi-Fi amp recommendation

No info on what amp and sound characteristics are most important to you, what you're looking to improve upon, or your budget.  You won't get very helpful or meaningful recommendations without sharing this critical info. 

To follow up on @soix 's comments, you need to tell us the speakers you are using and the size of your room. An amp needs to be matched to the speakers.
Also, are you using a preamp?

i payed 1200€ for the Naim 5si.

this is the clone Nap 200 and i see its about 200€ + shipment + tax, so might be 300 at the end. sound characteristic is really similar to the 5si, classical Naim sound. this one just has more power, better control in bass, deeper, and better clarity and cleaner highs. 
http://s.aliexpress.com/6vYnQrQJ

I was only driving small B&W PM1 speaker, but i felt an improvement! If you have a floor standing speaker, bass will be out of control with an 5si, and then you feel the improvement much more with the Nap 200. did the test on some B&W 683. 

But to be honest, once we switched to a Rotel 1552, bass became better then the Nap 200. A funny successful trial was to skip the preamp and control the rotel with a simple sonos connect. works absolutely perfect and reliable! really a simple soluion if you like streaming spotify. you can even limit the max output in the app. 

now your link works. yes that the one.