I have noticed that the optics ready m&p full sized pistols are getting the new trigger as well so my question is can you put the new trigger in an older m&p? Or does it have a modified trigger bar as well? I am a certified armorer so tearing the gun apart doesnt scare me but would rather have the new trigger in my perfomance center than in the plus.

My understanding is the plus trigger only fits the plus.

You cannot use M&P Shield PLUS trigger for any of other models.
There is no clear explanation from S&W if that new flat trigger from M&P M2.0 Optic Ready will fit other M&P M2.0 pistols.
Perhaps phone call to S&W customer service will help?

If this new trigger comes with extra cost, I would consider APEX Flat Trigger Set.

And he's good for everything.