I don't make that kind of assumption with expensive pumps.
If you really want to know, call Tuff Tork.
You're right ... if he has a plan to use a hydraulic motor of any size. The problem there is the limited flow and low pressure available. The motor could only develop about 0.7 hp with stock hydraulics. If all he wants is to use a couple of cylinders, that is not a problem. The difference between full extension and full retraction is the volume of the cylinder rod as far as the reservoir is concerned. All 6 of the cylinder rods (71" of stroke length, most of it with a 2" bore) on my GT and loader total only about a quart of oil from the reservoir. The reservoir on a X580 contains 5.6 quarts and being a quart low for a relatively short period of time is not going to hurt it. If the fluid level gets too low (down about 2 quarts), the hydro will quit moving the tractor and the cylinders won't work.
It all depends on what he plans to use the extra capability for. A log splitter is not feasible if you want production. On the other hand, a couple of cylinders to raise and angle a front or rear blade is exactly what the system was originally designed for.
What other shortcomings were you thinking of?
As a previous owner of a 2018 X580 I would like to point out a few facts. I purchased my 580 with the full intent of performing ground breaking/moving work. I had loam to move, hills to grade, snow to move, seed and fertilizer to plant/spread, large loads to haul (1500lb), etc..
I was successful in every instance when using the machines existing hydraulics and the attachments designed for the machine. That includes the 48" blade, 48" deck, powered (hydraulic) integral rear sleeve hitch, box blades, rakes and tillers.
There was no need to install or upgrade to additional hydraulics to perform any of this work with available attachments, and my only wish at the time was that I had a 3pt hitch giving me the ability to use heavier attachments, and additional hydraulics up front for angling blades etc..
Once I settled into the fact that I needed a larger machine for the next half of my property project I settled in on an X738 with 3pt hitch, full hydraulics up front, 4wd, and deck. After receiving the machine this past spring I began the process of modifying or replacing my attachments as needed, and purchasing a few attachments supported by the additional machine capabilities. Those included Imatch, grapple, and the additional up front hydraulics which support the grapple and front blade angle. My plan worked as I imagined it would and I now have a machine large enough and capable enough to support my needs now and in the future.
If the OP needs additional hydraulic capabilities I will say, based on my 580 ownership, that he is wasting his time and money upgrading his 580 hydraulics for any number of reasons which may include but are not limited to;
Warranty void, service, capabilities, available attachments to fit the 580 frame, time and materials to modify, and so on.
And, although the K72 is an incredible transmission fully capable of supporting ground engaging attachments, it is not even close to being in the same league as any of the K90 family of transmissions, period, end of subject.
So, OP, do the right thing. either use the X580 to it's full potential as designed, or jump to the X7xx series as I and so many others have and never look back.
Then you can put a grapple up front!!
John Deere X738 4wd
Front hydraulics and quicktach mount
54" front blade and 3 point hitch
48" mower deck
48" roller, 48" York rake, de-thatcher, aerator, 48" box blade
15HP 5" PowerKing chipper, JD 125# electric spreader
Assortment of sleeve hitch adapters, 3500# hitch mounted winch
Kubota G2000-S 52" deck, 21HP 3 cylinder gas, hydraulic lift
Vietnam Veteran 71'-74', USN recon 1970-1978