Hello Chiho -
With respect, I would suggest that you are barking up the wrong tree with your question. No matter what opinions are offered in response, the only opinion that matters is yours. It is ultimately up to you to decide the value or quality of your system, and it takes time and experience to develop an informed opinion.
Your DNA-125 Gold-upgrade is an excellent amplifier, has made quite a few audiophiles very happy, and certainly competes strongly in the price range you mention. Is it the best amplifier in your price range? Well, reasonable (and unreasonable) people will disagree. This is a question without an answer, or one that only you can answer in the end. I can tell you this: your DNA-125 Gold is an essentially honest, very transparent amp. It will drive most speakers well, and will accurately reflect what you feed it. Feed it well, and it will treat you well.
It bears mentioning that the great majority of any systems personality is largely determined by your room, your choice of speakers, and the location and setup of your speakers within that room. I urge you to give this due consideration before you change equipment. A bit of effort (and perhaps a few dollars) invested in room acoustic treatment will usually pay-off handsomely. Experimenting with speaker position is crucial, and there are a variety of helpful guides available online if you will search. One simple example: say you have your speakers setup along the short wall of your room and you are unhappy with your bass performance and soundstage size. In this instance, your listening position may lie on top of your rooms major bass cancellation nodes, and your speakers may be close enough to the side walls to cause soundstage constriction. Shifting the speakers to the long wall can go a long way toward correcting these problems. That may be simplistic (and easier said than done), but I hope you get the idea - be sure you have done what you possibly can to get the most from the equipment you have before assuming that changing any piece of gear will suddenly deliver you to sonic nirvana.
Whatever choice you make, I hope you will find your way to a system you can sit down with happily and enjoy beautiful music.
Best regards,
Steve McCormack
SMc Audio