Ditto to all the comments above. I am still using the stock 15" wheel ( wilth better aftermarket tires) and I feel that with the better suspension, lower profile tires will help significantly; am planning on 215/45 17's soon.
Also, on smooth roads, there is only a slight difference in ride quality, on rough roads, there is a pretty big difference when you get in to the high end of the progressive rate springs, but the handling difference is worth it ( with your lower profile tires, expect this to bea bit rougher).
On ride height, I barely noticed any difference before and immediately after installation; probably due to my old springs having 65,000+ miles. I can see that it is taking a set now after 4000 miles on the kit.
Overall, highly recommended