Is there any reason at all to install my pierburg?
 

The more stuff I change, the more the car will be screwed up. It only has 28K, so a new filter, MS, and a pressure gauge should be fine instead, correct? I guess when I want big boost, then the 550s.

no. stock fuel pressure is fine if you use properly sized injectors. (450-550)

So you are running stock pump at 12psi?

yeah.

other benefit of EM, you can run larger injectors without having to raise fuel pressures.