I know we have had discussions about topping UPP. Most people claimed they saw no difference including myself. Last night due to it getting dark, I didn't have the time to let EX sit for 45 minutes, so I put S100 on over two layers of EX. When I put it on I didn't notice much other than the car looked good. Today my car looks really really good. The S100 brightened the EX. So I have depth and high-gloss. It is not a huge difference but I do notice the difference and was well worth the 15 minutes to wax my car. I took pics and will be posted when I finish the roll. I will probably put on another layer of S100 in the next few days just for fun. It seems the S100 looks better the next day.