Location of compoments.

Agree with @ozzy62 - the details of what you're putting in the middle, and how (flush with baffles, or further back?) makes all the difference. I do gear to the side for one system, and in the middle (but pushed back) for another. Both do great, and I'm not stressing one way or the other. The logistics of each room dictated the positioning. 

@mulveling , do you go with long speaker wires or long interconnects?

I've done both ways - most of the time I've used 5m XLR (preamp to amp) with normal ~ 6ft SC's, but recently reconfigured it to shorter XLR's with 16ft long SC's. And that works great too! Ideally I like to have silver in my SC's, and that becomes cost prohibitive at longer runs, so overall I'd pick longer XLR's. 

How can a rack on the side not mess with first reflections ?

Because you don’t plop it onto a 1st reflection point lol. Ideally it should be at around the same depth into the room as your seating position, or even further back.

If you have a turntable source (like me), sometimes moving the rack further away from speakers has its own benefit. IME, much more of the problematic stray energy is structure-borne, not air-borne. If you use subwoofers w/ vinyl - good luck lol.

@lovehifi22
For long XLRs, I don’t go crazy on the exotics. I hit up the used market for whatever of the older-line Audioquest 5m - 6m cables I can find, preferably with air tubes. These use good quality metals, and don’t mess with the sound in any particularly vexing way. Their older copper models like: King Cobra, Jaguar, Panther, Columbia, Colorado, Water, Earth - are all very good, and still sound good in long runs. I don’t need their expensive new lines’ "Zero" tech. On shorter runs and if I feel like splurging - sure, I love silver.