Do I have to have the speed proportional steering feature for replacement rack and pinion, like my old one?

I would recommend getting the right rack. A missing speed proportional steering module will set a diagnostic fault code in the Transmission Computer.

You are working on the most miserable model Chrysler ever made for replacing the rack. I replaced dozens of them under warranty for making a tiny little "chirping" sound when starting to return to center.

By now you've noticed the cross member has to come down about six inches to get to the hose connections, but the pressure hose only has about one inch of slack so you can't lower the cross member enough to get to the fittings. Being the only suspension and alignment specialist, I did all my work on the drive-on alignment hoist which made it real hard to get to those fittings any other way. Not having the car on a hoist is going to make the job a whole lot harder but if you turn the wheels fully left, or remove the left wheel, you can reach the fittings with an 18mm crow's foot wrench, a pair of extensions, and one or two universal joints. Removing a 10mm nut behind the valve cover will also let the pressure hose drop a little more.

Be aware of the air bag's clock spring under the steering wheel too. Once the steering shaft is disconnected from the rack, you can spin the steering wheel endlessly. That will destroy the wound-up ribbon cable in the housing. The best practice is to have the wheels perfectly straight ahead and the steering wheel centered when you disconnect the shaft, don't turn the steering wheel from that point on, and be sure it stays that way when you reconnect the shaft to the new rack. You can accomplish the same thing if you turn the wheels, lets say fully left, disconnect the shaft, and put the new rack fully left when you reconnect the shaft. Regardless of how you do it, if the steering wheel is turned one complete revolution when the rack doesn't turn with it, the ribbon cable will not be able to stretch far enough when turning one way and it will tear apart, or it will have too much slack the other way and will fold over on itself and eventually crack. Replacement clock springs are about $150.00.

If you DO damage the clock spring AND your car does not have cruise control, I may have an almost new one here. They had to be replaced when the factory cruise control was added by the dealer. I saved a lot of the old ones.

All of those I remember doing were on four cylinder engines so yours might be different. That nut was on the back / top / driver's side of the head, just under the edge of the valve cover.