ALL sun conures are LOUD but not all sun conures are noisy.
The noise level can be controlled with proper training. THAT is where your issue is likely to be.
Sun conures are not really good apartment birds because of their pitch. However, I live in an apartment building and only one person has ever complained (but she complains about everything).
That being said, Skittles still makes noise but he doesn't do it for hours on end.
Not sure what the laws are in your state- but in mine, its nearly impossible to evict someone for "making too much noise" during the day. If its 1a, thats a different story. Or if it is going on for hours on end, every day for a prolonged period.
I have had a LOT of birds over the years and Skittles is the most quiet bird I've ever had (though he wasn't always as quiet as he is now). Yes, he's still noisy, but its nothing unreasonable. It used to be, but with proper training its manageable.
But each person has different limits. I am not bothered by the noise, but others may be so I keep it under control.
My advice to you is to think about it some more. If its going to be just you and the sun and if you're home most of the time, it may work out. But if you are gone a lot, have other pets/roomies or live a hectic lifestyle, it probably won't work out.
My advice is talk to your neighbors and feel out the situation. That may answer your question right there.
PS I also want to echo what Kalel said. You may be better off with a different species.