You're just learning some of the basics of hifi the hard way.
There are a lot of variables with hifi. Starting with the interactions of your speakers and room, the synergy of amp and speakers and finally your own personal taste. You need to get all these right to be happy with the sound, and notice I didn't mention money here. If you get the above compatibilities wrong, you can spend thousands and still make the same mistakes. Many of us on this forum have already made these mistakes, have learned from them wnd have some helpful experience to share, so before you faff about with biwiring with your brother (which won't make a scrap of difference to the sound balance), have a read of some of the comments others have made on this thread and listen to them. Some helpful suggestions have been made.
You can reduce the likelihood of these mistakes by demonstrating as many amp and speaker combos as possible. I'd always begin by choosing the right speakers for your room (because if you get that wrong, nothing will correct it, so don't expect 4ft high rear-ported 3-driver floorstanders to sound great in a 10' x 12' room, for example), then choose the right amp for the speakers, considering your own taste in each of these decisions of course.
If you talk with your dealer, give them a fighting chance by explaining the details of your room size, speaker positioning (how close to the walls will they be?), your musical taste (take CD's or a USB stick of music you like and know well), your likes and dislikes with sound and if possible, by listening to as many combos as you can, find out what you like. Then arrange to take the components home, but ideally on a home demo, or at the very least, if you're not happy with the results, a pre-arranged agreement that you can swap it for something else.
If you put bright/forward sounding speakers on a bright/forward amp in a reflective room, don't expect miracles. Of course it'll sound brash and shouty. So if the result sounds wrong to you, then one or more of the parts of the chain will be wrong.
There are components that carry house sounds, so if you don't like bright, punchy detailed sound, but prefer warmer, full bodied sound, there are certain brands to veer towards and some to avoid.
If you don't want to go through all that, just get some Dynaudio Xeo 2's (active speakers with their own amplifier and DSP room correction) and have done with it. Of course, I can't guarantee you'd like them.