I wouldn't do all black. Red stitch looks good. Red stitch with red inserts sounds like a winner. Perforated inserts sounds even better. Perforated red suede inserts is better still. As long as you match the stitch to the inserts it will look great. If stitch isn't available in maroon, then go red with everything. It makes the decision easier.
Once you pick a theme you're stuck with it, so you're right to take your time on this decision. A pure red is going to be easier to match than a maroon if you want to do other interior enhancements. Red LEDs are easier to find than maroon. Red piping is easier to find than maroon. Head unit's sometimes come in red lighting, but not maroon. I'm just throwing out some things. Red AND maroon isn't going to look awful, but you'll have 3 colors going inside.
2011 Toxic Orange R/T Classic Auto
Audio Mods: Pioneer DEH-P880PRS, Zed Audio Leviathan III, Hifonics Brutus BXi 1610d, 2x Infinity Kappa Perfect 10.1s (IB), Dynaudio Esotec 362 (active)