toto 15 inch rough in

hi replacing my existing toilet with toto drake elongated..my rough in is 15 ....can i use the unifit 14inch..what problem s will i encounter? ty

No, the Unifit only works with the Toto toilets that come with them.

That would be models like the Vespin, Carlyle and some others.

so if i use the right toto no prob with the 15 inch rough inand unifit ..just a littleextra space behind right

On the Toto's that use the unifit adapter, they come with the 12" one; a 10" or 14" version is an optional extra cost item. This adapter is installed on the flange, then the toilet is set on top of the adapter and anchored to the adapter. So, yes, any Toto that uses the unifit adapter (not all do), can substitute the 14" version for the 12" one that comes with it.