After getting a large plasma screen TV I did notice that the graphics on Mario Kart (Wii) were not as good as I would like. I was using the cable it came with (Composite Video + 2 Audio) without any adapters. So it was giving the best it can!
After installing this cable into the TV component connections and selecting the HD output (480p) in the Wii Menu, the difference was quite noticable. The colours were even more vibrant and most of all, the picture was sharper. So if you have a large TV with component input, this is a worthwhile improvement.
Cable quality seems very good and for me the length (2.5m) made connection to a wall mounted TV practical.