Is it worth it to upgrade a mod after obtaining the max speed?

Rounding out your speed secondaries is probably more important right now, but later on when you’ve got a few finished sets of 5 speed ticks it could help to try for a good second secondary. Generally Offense, but some characters may value Health and/or Protection more, or even some of the niche ones like Potency, Tenacity, Crit Chance, or (gasp) Defense.