904 transmission shifting adjustments

I don't mean to be a jerk or anything but I am going to say what I think, and others probably think but are not saying.

It seems to me you are putting an awful lot of emphasis on parts based on how fast it might go instead of how long it will go.
In my opinion you need to get some basics straightened out before you spend a bunch of money on go fast parts.
Your car will be the most expensive car broke down on the side of the road if you keep doing it this way.

Get the throttle pressure cable kit and get that trans working right.
The cable isn't there to be tied in one place, it's supposed to vary when and how hard the trans shifts from one gear to the next depending on throttle position.
That power steering line for the cooler lines was a good call, maybe a little overkill but better than burning the trans or the car down from spraying fluid.

Just my own opinion obviously.