There is only one backhoe that is widely used on BX tractors with 4 digit numbers; that is the Woods BH6000. This backhoe is about 3% stronger than the bh that comes on a
BX25. The cost to add the backhoe later is $1500 to $2000 more than just buying a
BX25 up front, however. The reason for this is all the extra shop time to install a sub-frame, replumb hydraulics, change to the lift-up/swivel seat, etc. The bh that comes with the
BX25 is a bit easier to reattach than the Woods. The only people who have claimed that the smaller ROPS may be a problem are people who have never operated the Woods on a BX. The BH6000 can be used on any of the 4 digit number BX tractors, even the little
BX1500:
http://www.tractorbynet.com/forums/kubota-owning-operating/54527-bx1500-woods-bh6000.html
Do not be fooled into thinking that the 2660 has more horsepower. That number is achieved by spinning the crankshaft at higher RPMs. When the engine comes under a load, the torque will still be the same. Bore, stroke, compression, displacement, etc. make more difference in true power than simply spinning the crankshaft at a higher speed under no load to get a higher
peak hp rating.
There are endless threads in the archives regarding whether it is better to buy a two digit numbered BX (22, 23, 24, 25) that comes with a bh, or go with a four digit numbered one (1500, 1800, 1830, 1850, 1860, 2200, 2230, 2350, 2360, 2660) that does not come with a bh. You could spend several days reading all the debate if you wish to dig it all up by searching the archives.