Well, generally speaking, lowering springs are stiffer for less body roll and handling- from my experience. You will have less suspension travel before bottom out, so should you hit a big bump with the tongue weight it may be more harsh. My biggest concern will be the load capacity of your tires, low profile tires are often not rated for much weight as they trade off daily capability for performance.
As long as your boat isn't too heavy, and you get a proper ball mount for your new stance, it should be fine. If you don't get a new ball mount, your trailer could pitch forward, resulting in more tongue weight and thus more sag.