The lead in the gas that used to be necessary to keep the valve faces and seats lubricated will coat the inside of your catalyst and screw it up good and proper.
Why do you need 110 octane? Are you boosting 1.5 bar? Got 13.5:1 c/r?
I ran 110 octane in my 11.5:1 Kawasaki and it ran like s**t.
i dunno about it being legal and what not but i know if your car isn't tuned to run higher octane you will mess up the injectors, fuel filter and so on..
at work we had a h22 prelude come in complaining of bogging and backfiring and such....he neglected to tell us that he put straight cam 2 in his tank...
i know he fried the filter and his injectors were clogged horribly