It'll drop the height sure. it'll make the ride stiffer. The shocks will wear quicker.
It will reduce roll, reduce height, increase more negative camber, increase lower centre of gravity.
Decrease comfort, decrease shock life.
Pretty basic stuff really. Springs are okay if you just want to decrease height. But that's about it.
If the springs are pretty worn anyway changing them for new will improve things anyway.
But ideally you want springs and shocks to match.
But I am sure you know this already.