Skins,
In my last post I went on for quite a while about the ROPS. I feel that is a very important safety feature. I've read a lot of posts from people who have said how unstable tractors can be when operating a FEL. Therefore, I think it is a necessity. If the cab has to be removed to install the ROPS, then the cab is essentially unusable. That's if you feel the ROPS is necessary. Something to think about.
I would think the tractor is mechanically sound. If you had some hesitation about that, you could probably find a local Kubota dealer and ask if a service person or mechanic could stop by and check it out. Might cost maybe $100, but worth the money to have someone familiar with the model and mechanical features check it out.
Final thought from me. Three issues to sort out. Getting ROPS installed, GST vs HST, and cost of old vs new. I'd have to have ROPS for all uses. I wouldn't be putting it on and taking it off. Is the cab then useable. Could sell it, but is someone else going to want it if ROPS has to be removed? Hmm? GST was a significant improvement over grinding gears with a manual transmission. And in certain jobs like field work that doesn't involve pto, I would think it would be super. But operating an implement that runs on the pto might be a little tricky and doing loader work a bit busier for the operator. Just as GST was the new age of transmission from a manual, an HST serves the same advancement from a GST. That's just my opinion, and it may not be totally true or worth a hill of beans, but that's the way I see it. That doesn't mean the GST is bad. Some people love manual transmissions and GST and HST. Tough call. Finally, if I'm a few thousand apart between new and old, I'm going new if I can get more of exactly what I would want with warranty. Hey, it's a Kubota and a great tractor. Thanks.