steering mods

[yaris9876]

This is about a 99 sienna Van but its a Toyota and I have a Yaris....640K miles truly.Original all including clutch. But it shudders a little bit..
If I ask about mods on most sites the establishment jack asses always get scared and say dont do mods...stick to stock...they make me sick.Yaris people tend to have guts or they wouldnt have bought a tiny Yaris anyway.
The power steering H pump on the Sienna needs replace. I really would like to change it back to a simpler set up. Pull out the hydraulic ram and just go bck to rack and pinion
with a old style steering box. The hydraulic set up on Siennas is known for failing.
I dont know if those steering boxes have power or not. I know they have oil of some kind.
Has anyone here done any mods on their steering systems???? Can you get a 12v powered steering box that would help turn an offset knuckle like you find on Rack and Pinion.??? I dont know if we have many mechanics on the forum...I hope there are some..