The
BX2380 and
BX2680 only differ in the engine, the rest of the machine is identical. The
BX23s is based on the 2380, with the addition of the subframe and backhoe. I was under the impression that the subframe and backhoe are factory fitted, but there's a Messicks video out there on youtube (I think about backhoes) that has pictures of the subframes in a stack, which might indicate they're actually dealer fitted or at least dealer assembled.
So, in concept, you could take the backhoe components from a
BX23s and bolt them onto a
BX2680 instead, making a BX26s. In reality, I suspect you couldn't order the parts to do that in any economic way, so you'd end up with a very expensive tractor (at it's most extreme, you'd buy both a
BX23s and a
BX2680, and then shift the backhoe onto the
BX2680, selling the residual as a
BX2380, but one that wouldn't be worth as much as a new one....)
I guess the question is why you'd want to do that. It seems that Kubota think the 23hp motor is plenty to drive the loader and backhoe - more HP won't make the pumps run any faster. So unless you have some other application that you'd use it for with the backhoe off - probably something you were planning to drive from the PTO - it's not clear why you'd bother. The general internet wisdom is that the
BX2680 has no purpose other than being the "more power" version of the
BX2380...it doesn't have enough traction or weight to use the additional HP.
Of course, I'm looking at a new BX, and I'm probably gonna buy the
BX2680 anyway just because I can....it's not much more money.