Q on Waste Pipe Size (3" / 4"?)

[HouseDestroyer]

Hello - I have a fairly simple (or dumb) question about the waste pipe size that toilets use in the USA (and if your really competent, I would like info on the UK). My house is from around 77-79'ish (if that helps) and I am confused on the standard toilet waste pipe size. I am looking at bringing a toilet from Europe back to the states [screw local codes... tho it is still 1.6gpf, ill take it out when i leave ] (output via S pipe on bottom) but I think most toilets are 4" in UK... my concern is that If my pipe were to be 3" i would be out-of luck for a novice DIY-guy. Toilet facility has never been moved in house-history. If someone could help me before i dig the toilet up. would only like to battle with it once (if i get the UK toilet). Any positive information is greatly appreciated. Thank You

[hj]

Whether it is 3" or 4" is immaterial. The floor flange that the toilet fastens to is a standard size. The only difference is the size of the outlet hole in the flange.

[Marrkk]

As the previous poster said, the U.S. flange is the same for both sizes. The REAL question is what is the size/mounting method of U.K. toilets. I know european toilets are sold here, but are they redesigned for the US market so they fit?