I cannot speak for the one piece Champion but I have not had good success recently with the two piece version. The troubles I have had are customer complaints about the flush valve "tower" banging after a flush, the refill tube, (rubber hose) coming undone while the tower drops, the small area of water in the bowl and the price. Some of these things led to callbacks which I despise. Needless to say I stopped selling them.
http://www.totousa.com/toto/ProdCatalog.asp?cid=10[/URL] Toto, is another brand that has all the options you mentioned.