Kinda late, but I would pass on the Nitto 450's. Probably the worst tire they made when they first came onto the "import scene". I had sidewalls "bubble" on me when I had them on my car.

I would probably steer clear of the 502's. Nothing wrong with Falkens, I like them personally, but I had the impression that they were no longer in production, so this might be really old stock (replaced by the Ziex 512's). Ironically this is what I used to replace the 450's that I had on my car.

No personal experience with the Kumho's or the Sumi's, but you could probably get enough user reviews from Tirerack.com to see which of those two would be better.