First off, welcome to the forum!
The 50s will be a bit smaller in diameter and circumference. There are many online calculators, or you can always look up the tire on Tire Rack to find specifics, but looking at the first tire I could find available in both (Blizzak WS-70), the diameter of the 50s is .9" smaller.
You'll lose roughly half an inch of ground clearance (if the diameter delta is .9", the radius delta will be .45", thus losing .45" clearance), but the car will be lower with lower profile tires (typically better for handling). Also note that the max load weight might be a bit lower, and your speedometer might be a tad off. I wish I could tell you if it will read faster or slower than reality, but I can never keep that straight lol.
Bottom line, your car will be roughly half an inch lower, but probably perform a tad better. You probably won't notice much unless you need the clearance for off-roading or snow.