The OP is talking about a 52" Scag Tiger Cat here.
According to Scag's site, they offer a 25 and
a 26 Kohler EFI on the 52". That must be a misprint. Kohler doesn't offer a 26, but they do offer a 26.5 (which is 25.5 under the J1995 rating). The 25 is 24.2 under J1995, so obviously the the larger engine would be the way to go in EFI.
In checking with the Kohler site just now, I see the 27's they currently offer in a vertical carbed engine are rated at 26 and 25.9 (the latter of which is brand new) respectively, so they would be stronger than the 22 Kawi. Seeing as how some manu's are still using engines that were originally labeled under the old system though, it is very hard to compare apples to apples, and seeing that kohler is still fudging the HP numbers by at least one, even under their new system, it makes it even harder.
I still wouldn't buy a Kohler unless it was EFI. I have had just that much bad luck with my last two.