RTV X1120D Heater

Has anyone installed a heater in a RTV X1120D? I am thinking about putting a heater in my 2013 and I have read the installation manual for a Kubota OEM VC5083 heater kit. Has anyone installed that kit? Only issue might be drilling holes for ductwork to vents, especially since I already have a cab with windshield that make it difficult to drill two upper holes. Probably have to remove windshield and more to get those holes cut. I am also wondering how effective the barrier included in the kit for blocking cold air from getting into the cab is? The kit and wiring is about $650. Pricey but that's the way it is.

I have seen aftermarket heaters that are cheaper but I'm not sure they might be as effective.

Anyhow, just looking for some ideas, experiences, with the OEM heater or other heaters for a Kubota RTV X1120D.

Thanks.

RTV X1120D Heater