I don't know! But, you'll really like the soft-close feature, the kids will use it just cause it's neat to watch. Might get them in the habit. It also prevents that late night slam that can wake everyone up, too. Little fingers slammed under a "normal" seat are less of a problem, too.
I think that the bolt hole separation is standard. You could check out www.totousa.com web site and get the measurments and then check some other manufacturer's sites to verify. The TOTO seats exactly match the curves, others probably would work, but may not look as well. Same is true with the color match, you might get close, but probably not exact (even with white - toto has two different whites). The way the seat fits, you probably couldn't use a seat cover, if thatis your preference, though. If you're going to cover it up, I guess there is less of a reason to go with the TOTO.