[serialk11r]

Adjusting the flow control valve would be trimming the spring a little so it opens earlier. The rack will be slower, but if you can turn the wheel okay at idle I feel like it's not an issue. Better would be to just delete the PS and loop the rack, but you'll have to muscle the wheel a bit. If the spring was trimmed too much, you have the option of boring out the flow control orfice to undo the change a bit.

There are probably better gains to be had from the water pump. Due to the constant-flow-output design of the PS pump, the energy loss through the rack is fixed, and the energy loss through the flow control valve increases linearly. The water pump has no bypass valve so the losses grow cubically. At like 2500rpm the water pump is usually already eating a few headlamps worth of power in excess of the engine's cooling requirement.

As for the air dam, you could start with extended tire spats first for something easier and less conspicuous/fragile. They don't add frontal area and only improve the Cd, while an air dam increases the frontal area.