What exactly are the R&D numbers and what impact do they have, if any, on the apparel? I’ve inquired a few times in the past but never received an answer that made any sense (or maybe that is the answer, they don’t make any sense).
Nobody seems to know why the call them "R&D".
Think of them as "points toward your next upgrade" for that particular apparel item. So "R&D +12" means you just got 12 more points toward the number needed for your next upgrade (1000 points needed to upgrade the MAX hat in John's example).
If you already have an apparel item maxed out, any further points you get for it are converted into coins (2000 coins per excess point) and you get the coins instead.