You're not seriously thinking of reusing the same coil????Do not even in jest continue with that line of thinking.
Get a whole new system where everything is matched to each other.
Now lets get back to the original suggestion.
You have no idea if your house needs a 3ton a 2.5 ton or a 2ton.
You know if you have the wrong size unit it costs a bit extra each time it comes on.Now thionk of the thousands of times a unit comes on durning its lifetime.Are you that rich????? Have a load calc done and know what you need.
By the way you will also need a new line set.