If you go to the Kubota site and build your Kubota there is 700 dollars difference in MSRP. I would translate that to 300-400 dollars max. You MUST get the skid steer quick attach. It's cheap now but almost cost prohibitive to add later.
I have the L3240 with the 514 loader and have had no problems with it. I am currently in the process of building Momma a mound for a waterfall and have moved a lot of rock. The tractor will lift anything I can get in the bucket with no problems at all. I have had to push some rocks but they are about a 4' around or larger. I have used the loader for a lot of heavy work; lifting 5/8- crushed rock and 1 1/2"- crushed and it has done just fine.
I have the heavy duty bucket with the bolt on edge and am extremely glad I purchased that. Digging out rock and moving it takes a toll on the bucket. My bucket isn't pretty any longer but neither am I.
Enjoy your purchase and have fun, er, um, I mean work it as it was designed to be.:thumbsup: