I usually don't like to post on these forums, love to read them and study and learn from what others are building and doing though. I have been intrigued by electric power steering units for a while now too. But I have found a less expensive solution that is working for us and may for others as well.
What I found was that in the UK electric power assist units from factory cars are being used in motorsports and other applications. An electric power assist unit is not hard to find. Several cars run "in the column electric power steering assist units." Being able to control it and make it work seams to be the problem.
After alot of searching I found a guy on ebay that makes a harness that operates the units in place of the ecu and gives you the abililty to adjust the level of assistance you want or require.
Heres a link to the harness:
This harness only works with units from
Saturn Vue - from 2002 to 2007
Chevrolet Equinox - from 2005 to 2007
Saturn Ion - from 2003 to 2006
I found a unit from an Ion at our local salvage yard for $75.
Bought a harness spent roughly 7 hours making brackets and fabbing it into the car.
This 1st unit we put in my wifes car which is a 4 seat beam car with a 4.3 V6. 1760# pounds before anyone gets in.
Has a power adjustment from no assist or stop to stop with 1 finger.
We'll see how long the unit holds up but I bought another unit and harness and plan on putting it in my 5 seat LS project as well.
So in short $150 for power steering.
30 pack of beer, a Saturday in the shop working on the car with a buddy, followed by a BBQ. Priceless.