I have an excellent 8 year old 1.6gpm flush Kohler highline. Looking to upgrade as part of bathroom renovation. Latest version of Kohler and Toto <$1000 all look sadder than my trusty existing toilet. Looking at other brands such as Axent (Primus), Studio Lux (SLT1000) & Duravit(ME). Local dealer swears by all these brands. Would love to hear your experiences with these brands and with tankless toilets. Thanks in advance.