If your shirt is uncomfortable when you are sitting or moving around, it doesn't fit perfectly. Your shirt should be comfortable throughout the normal range of movement that you would expect to encounter when you are wearing a dress shirt. You don't need a performance fabric, you need a shirt that fits correctly.I'm going to agree with @medhat.
To point #2, I have a couple of bespoke dress shirts (not MTM).
While they are incredible works of art, and do fit well, they generally look and feel their best when I'm standing upright. If I sit down, or move around, they can feel tight around my mid-section or even chest, and as such, I tend to feel a bit more uncomfortable than I'd like.
For that reason alone, I don't wear them very much. Also, if I go up in weight some (even slightly), which is an issue I've dealt with since a child, the shirts fit too tight in the midsection.
Or maybe the tailor made the shirt the way you told him to make it. Proper fit is subjective - to a point. If a shirt is uncomfortable when you are sitting because it is too tight in the waist, it doesn't fit.@barca10 - Well, I had a pretty well known bespoke tailor make my two custom shirts, so I'm not sure why they wouldn't fit as "they should".
They are my only two bespoke shirts, so either:
1. They aren't ideally cut
or
2. I don't like the way [these particular] bespoke dress shirts fit me
Also, I don't see any reason why a proper fitting shirt couldn't also be made with performance fabrics and/or have spandex/lycra.
There are valid reasons why performance fabrics could be welcome for some over other fabrics, as I stated in my last post.
Clothing and fabrics continue to evolve, and one man's definition of comfortable or proper fit isn't absolute -- it's subjective.
