AFAIK, you have an untreated 3x4m room, very little interest in getting a subwoofer and even less interest and no experience in room acoustics or doing measurements in your room.
Also, you want a cheap, but state of the art system. Your dream speakers are the Genelec 8361, but they are too expensive. You are looking into other Genelec options, but they are also expensive and have drawbacks, like the more limited bass capability of the smaller Ones.
Because of this, i think for you the KH150 + MA1 would be better than the KH310.
- I expect it to be way easier for you to get the KH150 + MA1 sound "right" in your room because of better directivity and the automatic alignment.
- If you are getting the KH310 without the KH750+MA1, it will be difficult in your room - i think i know what i´m talking about. I think you will probably be disappointed.
- If you don´t believe it, try for yourself, like @thewas wrote.
- The KH150 is "state of the art" in the sense that it is currently the best in class product without any reasonable compromises or important drawbacks (that i know of). You can tell everyone you have a system in your room close to what´s possible within reasonable borders. It surely is "good enough" for every realistic pro or non-pro use case in a small room.
- You can make a good start for around 3,400 EUR (2 KH150+MA1 using bundle options), but you could easily add 1 or 2 KH750 later, if needed (i suspect so). So, for around 5,000 EUR you can get a fullrange system, that is very close to what´s possible in a small room. Most importantly, you may get out of your obsessive (sorry, but this is how it looks) loop of searching for "the" best speaker.
- From there on, the most important limiting factor is the room itself. A lot can be achieved with treatments, though.
- If you want it to be even better, you´d have to invest much more money: e.g. for a Genelec One (+GLM and Sub) system, a multisub system or something like Kii or D&D 8c. I don´t know any of those speakers, but i doubt any of this will be worth it in a small room like yours.