If your reason for upgrading the size of your sump pump is because it struggles during occasionally large rain storms, it's better to add a secondary primary pump with a raised float. Doing this will allow the initial standard-sized sump pump to run during normal use, but in the case that the initial sump pump can't keep up, the secondary sump pump will kick in and help out.
In the case that you do add a secondary primary pump, you will need to increase your discharge pip to 2.5" or 3" to handle the capacity in the event that both pumps operate at the same time. Otherwise, you can add a second discharge pipe for the other pump
If your current pump is constantly having difficulty keeping up with the rise in ground water, you should consider increasing to a larger horsepower pump, and then possibly add a secondary primary pump for the more rare intense storms.
Up-sizing just for the sake of having the most power will cause your pump to cycle too frequently during normal use, shortening the life of the pump.