I have the standard blades on the x310 from when I purchased it, but was going to put the mulch kit and gator blades on in the Spring when I replace the blades for the 1st time.
if you want a better cut, go with the gator blades. They do a nice job of cutting up the discharge & help the deck act more like a mulcher. One thing to think about with a larger deck will be it can trim closer than the narrow deck, but as said above check clearances between trees so not a lot of trimming. I don't see it as overkill at all, and think of it as future proof against moving to a larger lot.