It's too hard to recommend anything. There are so many guitars to choose from, and everyone will differ in their opinions. What sounds good to one person might sound bad to the next man. Then there are features. Do you want the warmth of a rosewood fretboard, or the percussive attack and brightness of a maple board? Trem-equipped guitar or fixed bridge? Bolt-on neck or neck-thru? There are so many variables here, plus many differing opinions on what constitutes "a great guitar".
If I were you -and I'm not trying to influence your decisions here, I'm just saying what I would do- I'd just keep the Universe and sell the others. The RG2550 and RG1570 are very similar guitars; basswood bodies, Ibanez pickups, Edge Pro, Prestige Wizard profile maple neck, rosewood fretboard, jumbo frets, etc. etc. The Universe can do anything that the RG's can do, and probably sound better doing it. Why bother keeping two 6-string RG's that are largely the same when you have a superior guitar in the UV?
By the way you said "i allready own a rg2550,1570 and a universe but now i want an excellent sounding guitar", you made it seem as though you are not happy with your current guitars because they don't sound excellent, or "real". If that's how it is, why bother keeping them? If you buy some other guitar that sounds excellent, will you neglect your current RG's and Universe?
This is why I am suggesting to sell them and put the money towards a killer guitar. I love Ibanez, but they don't really make what I would describe as killer guitars. I play them because they are affordable and for the money, they play well and look good. If I wanted a killer guitar, I'd be looking to spend a few grand on something like a Suhr built to my own specifications, not buying as many RG's as I could lay my hands on.