I have an M&P 2.0 full size, and would like to increase the trigger pull. In my research, it looks like a major factor to increasing or decreasing the trigger pull is replacing the Trigger Return Spring. So, my question is if I replace the Trigger Return Spring with a Massachusetts compliant spring will that alone increase the trigger pull? I would like to increase the pull from it's current 5.5 lbs to maybe 7 to 8 lbs.
Thanks for any assistance anyone can provide.

The short answer, I believe, is yes. Changing the trigger return spring to a "heavier" spring would have the desired effect. I would suggest though that you contact Smith and Wesson Customer Service for confirmation, and for suggestions they might have on how to best achieve the heavier pull you desire.

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Ret. LE, FA Instr, S&W Armorer

I just ordered a couple MASS compliant trigger bars assemblies and springs, so I will find out soon! In all my research this appears to be the easiest way to increase the trigger pull, but I wanted to confirm with anyone that actually did it and what the end result was??

11-2-19 Update:
I received my 2 new Massachusetts compliant trigger bars and springs. I installed one set in my 2.0 compact 40 cal and raised the trigger pull from 5lb 4oz to 7lb 1oz. I installed the second set in my 1.0 9mm FS and raised the trigger pull from 6Lb 3 oz to 8lb 1 oz.
I accomplished what I set out to do! IMHO: a 10lb trigger would have been to hard, but I am completely satisfied with the current trigger pulls.
My reason for raising the trigger pull was for a stiffer trigger for my CCW activities without worrying about an AD/ND.

Thanks for reporting back. Were the trigger bars a necessary component along with the heavier springs for you to achieve the results you wanted?

__________________
Ret. LE, FA Instr, S&W Armorer

I believe if I just changed the spring, I would have achieved my objective without changing the trigger bar as well. But, who knows??
I compared the 2 trigger bars and there is a slight difference between the 1.0 and 2.0.
I have a couple of other M&P's I want to stiffen up the triggers as well, and I will only do trigger spring going forward. Cheaper, but the effort is the same if I did change the entire trigger bar and spring. Having the M&P's apart, they really are cheaply made on the inside and more complex than the Glocks.

I have just purchased a Mass compliant M&P40, 11764. I want to decrease the trigger pull closer to the 6.5lbs. Will changing the trigger spring give me the desired results? Where can I purchase the lighter spring? I am very new to firearms, however I'm also very handy.
I just purchased the gun a few hours ago and I won't see it for at least 5 days. I just started researching this, and from the little bit I've read states that the job is not very difficult and can be done by anyone with some mechanical ability and patience. Is this true? Do you folks find changing the trigger spring to be a difficult task? I also understand that if I choose the Apex route , that Apex has excellent customer service and will happily provide assistance over the internet or phone.is that accurate?
Thanks in advance for any and all advice.

Brownellsdotcom stocks both the trigger return spring (940-000-696) and the trigger assembly (940-000-971). You'd be best advised to get the proper size roll/spring pin punches for easy removal of the appropriate pin(s).

My understanding is that, depending upon how light you want to go, the MA compliant pistols use a different trigger assembly and sear housing block assembly than the standard pistol, (which uses 940-000-958 sear block).

You might want to be aware that, IIRC, at least as of 5 years ago, S&W didn't advise armorers to take the sear housing block assembly apart. (Yeah, it can be done but our armors stated reassembly was a royal pain. A stiffer sear spring is allegedly the difference between units, making assembly/disassembly of the MA compliant unit even more of a pain.) BTW, that sear block part number is for the standard block, no thumb safety.

If you aren't mechanically inclined, best pay someone else. Most gunsmiths/armorers charge extra for paper bag jobs (guy comes in with a bag full of parts-hopefully ALL the parts).

Thanks for getting back. I just received a spring kit from M*CARBO. I 'm definitely going to tackle this myself. Looks pretty easy. I'm thinking I may need to replace the sear to the 2 dot sear. I spoke with the tech at Mcarbo. He said there was a slight difference between the two, but wasn't absolutely sure it needed to be replaced. He suggested I try with the original sear first.
Called Smith and Wesson and they're closed until Jan 4th. I'll probably wait and ask them.
I'll let ya know when I do it. Not in a real hurry.

One other thing on assembly. I'm sure your guys were talking about lining everything up for reassembly as the pain in the *** they were referring to. Not much of an issue if a smaller slave pin is used prior to installing the roll pin.
Thanks for the advice on the punches. I have all the brass roll pin punches and flat punches necessary to do the job. I'm not foreseeing any issues. Unless a spring goes flying across the room. Which can happen! Ha ha
Thanks again