Have you considered the fact that with the current 25 hp engine, you are probably pushing the limits of the engine to produce the gpm of fluid that you need to operate everything at the same time. Using a hydraulics calculator, I figure you can pump about 12 gpm max at 3000 psi. If you modify anything, such as a larger tram pump, you may have to go to a larger engine. You can get by with switching to larger wheel motors, and get more torque, but you suffer in top end speed.
I would think really hard on changing all those hyd hose to find out that it isn't as good as what you have now.
I believe that tram pump is in the $1000.00 range, and if you do go larger, you will have to upgrade the current engine which is about $2200.00 to a larger engine which cost even more.
It is very hard to modify a proven concept, and be cost effective, and with more advantages over the old system. What ever you, I applaud your efforts.