Does carbon filtering (Grey Kangaroo) liquor (Vodka) improve the taste?

I know companies like Grey Kangaroo and Vodkastick make carbon filters to make cheap alcohol like Popov or Sobieski taste better. You poor the alcohol through the filter into another bottle which makes better tasting alcohol. This isn't very cost effective because you can only use the $25 filter 50 times and you're likely to filter 1 bottle 2 or 3 times each making the cheap alcohol cost more. Has anyone tried using one of these filters on more expensive alcohols like Grey Goose, Skyy or Absolut? I wonder if it could taste EVEN BETTER!?!? Then the expense might be worth it.... BTW, you could also buy regular activated carbon in bulk such as the stuff for aquariums to filter your alcohol for less money...