I've got it setup with Truglo TFX Pro sights and an Apex Action Enhancement Polymer Trigger & Duty/Carry Kit has been installed. I'm running the stock trigger spring for an average pull weight of 5lbs.
The grips on the M2.0 are too aggressive for me, so I knocked them down with some sandpaper. I tested on a backstrap that I wasn't going to use. Taped off the frame and had at it. Result is more aggressive than the Gen 1 M&P but about 50 ~ 60% of the M2.0 texture. As with all polymer framed guns in my collection, I sanded down all the mold lines with particular emphasis on the grip, trigger guard, and trigger area. I also ended up doing some gentle sanding of the trigger face because the slot with the tabbed trigger was bugging me.

Next I sent it off to Apex to have an Apex Grade 'gunsmith fitted' barrel installed. The biggest difference over the stock barrel is in the hood and lug area as seen in the photos. Also has a target crown. Apex is the silver barrel, black is the stock S&W barrel.



Apex turned this pistol around in under 3 weeks.
Results. Very encouraging. The test target was shot from a fixture, at 15 yards, 5 shots in 3 overlapping holes. from the initial rounds through it, I can tell that it's going to be a tack driver once I've gotten used to the trigger.
Is it worth it? From an economics POV, no. The barrel is $199. Labor was free on this deal, but Apex required that the pistol be overnighted to them and overnighted back to me. OUCH! I'm an FFL and found this ridiculous, but do understand it to a point.
My advice, if you want to go this route, is to order the same barrel but have your own competent gunsmith do the fitting. There's also a drop-in barrel option.
Am I happy with it? Yes, and I've long ago recognized that if $$ was the guiding factor, I wouldn't own half the firearms that I do.

* Considered upgrading the current pistol, but it's 15 ~ 20 thousand rounds away from needing a complete rebuild. At that point, I'll probably just retire it.