DAVID ARCHYMen's Underwear Ultra Soft Micro Modal Trunks Boxer Briefs with Fly Boxer Shorts

What is the difference between “black” and “black drop needle”?

What is the inseam?

When everyone says to order a size up, is that based off the sizing chart? i.e. the chart says i should buy a large, do i buy large or xl?

How do these compare to Calvin Klein modal boxer briefs?