I remember when I set up my 1.0 guns I used extra power striker springs because that was what everyone else was doing back then, you guys still doing that now? The springs in the 2.0 looked the same as the 1.0 so I grabbed and extra power from my parts box and threw it in, don't know if it'll make much difference but I don't think it can hurt.

This is the first I've heard of this and I've had several M&P's of various sizes over a decade. Never had a problem a striker spring would fix.

Guys were thinking that the extra power spring would help if you ran into ammo with harder primers. Probably was more of a feel good thing than anything.

I have a bunch of M&Ps and I have never had an issue with failure to ignite a primer due to a weak strike. Additionally, I would skip changing spring weight in a striker because it may have a negative impact in some other way. For example, shorter striker life, additional wear of the sear etcetera. The engineers employed by S&W figured it out and they put a decent warranty on their products.

Didn't know that was a thing. Never had a problem with 1.0 or 2.0s.

Same.

I had failure to fire issues with my 1.0 9MM FS M&P.  Two issues.  Neither of which was primers - but one of the recommendations 10 years or so back on the M&P forum was to replace the M&P striker spring(s) with Glock striker spring(s).  I had two M&Ps (9 and .40) so I just replaced both and those Glock springs are still in both slides.

Back to the failures to fire.  The stronger Glock striker spring did not fix the 9MM FTF issues.  The cause was two things.  Sear flutter and timing.  Getting some crud (funny looking debris in the well the sear spring sits in inside the frame as well as a new sear spring) fixed the sear flutter - indicated by no mark at all on the primer and a "dead" trigger after the next round was chambered.  An adjustment to the hoop/loop on the trigger bar fixed the timing issue - indicated by a small striker mark on the primer of the chambered round after hearing/feeling an odd click when pulling the trigger.  Striker would hit the striker block, bounce past and hit the primer, but not hard enough to ignite it.

I'm shooting that old 1.0 again now with a PC 5" slide/barrel kit on it.  Darn thing sat in the safe for almost 10 years while my CZ P07/P09 spoiled me.  

Different guns can be different.  My 9MM was full of problems.  The .40 was always good, even the trigger on the .40 was way better than the 9MM out of the box.  Just the way it is.

I have around 10K through a few 2.0s now. Literally 0 issues with any of them. I wouldn't change it unless you really had a problem.

Hells no. I put an MCarbo lighter stroker spring and haven't had any issues with hard primers.

I put an Mcarbo striker spring in my 1.0 PC slide (9MM) and the trigger pull went up 1/4 lb. vs. the stock striker spring.  Weird.  

I pulled it back out and laid them side by side and the Mcarbo spring was longer than the S&W spring.  Maybe the PC OR slides have a lighter striker spring vs. the standard M&P pistols.  I don't know.

FPNI

I compared the stock spring to an extra power and the stock spring was noticeably shorter.

I put the stock sitting back in the 2.0 but left the 1.0 alone.

That's super strange it went up. For me it lowered the pull lbs and zero issues with hard primers even with an Ed Brown skeletonized striker and Ed Brown extended striker block, which is supposed to assist in igniting harder primers and it has a noticeably cleaner break.

Are you guys having problems with steel cased ammo? I don't own a S&W M&P yet but I'm looking at a .45 shield. I shoot a lot of steel cased.

Ive never had a single striker issue in my 1.0

As with most people here, never had a single issue with both 1st and 2nd gens on stock springs.  All while using a wide variety of ammo, including a bunch with shitty primers