you could sacrifice one plating for even better cooling and regen... No, I already mentioned the mods on this guy's previous topic so I won't bring that one up again. (Ironically)
You could upgrade the unused epics to legendary for some legendary food.
In short, upgrade your grappling/teleport at the VERY end of upgrading your mech. Do not upgrade the hook just yet, that's for later. Plus you wouldn't really want to spend a total of 800k+ coins at myth just to max out a grappling hook, would you
I only upgraded my teleports (which is just barely any extra damage) when I'm completely done with everything, not when your first or second mech is done. They do play a role when playing, of course, but upgrading them while you're still finishing your first mech is an automatic no.