New to me SR40

I just picked up a used SR40. It appears to be in like new condition and comes in box with all the factory stuff. The spent casing from the factory says it was made in 2011. The previous owner removed the mag disconnect safety. I've put 3 rounds threw it to test it but haven't had time to get to the range for a full test. Being that the mag safety is out should I expect any issues or does this mod usually work ok? Also anything I should change to make it more reliable?

You won't have a problem sans mag safety. Removing the thing is something most people do. Probably not necessary for the vast majority of gunfights, but if you count your shots it's nice to know you can shoot 1 more bullet while you're swapping out the empty mag should the need arise, and it avoids the need to slingshot or otherwise release a locked open slide. It might save your life someday.

Removal of magazine disconnector is a good mod in this pistol. https://m.youtube.com/watch?v=8dHXND_9-bE

The main change to improve safety/function is to remove the mag safety. It's there because 'oh oh oh look look look some one could pull the trigger and accidentally shoot'! It's no accident if you pull the trigger on a gun that you havent't personally cleared!!

The SR40c is very well built and due to design and dual recoil spring assembly (RSA) will reduce the felt recoil of the 40SW. Many pistols don't have a magazine disconnect, so removal of this one will not be a problem.