I've read several times that the stock turbo is tiny.
If you follow this link:
You will see in their maps that torque tapers off as rpms increase and it says the boost target is 20.5 psi peak tapering to 13.5 psi at redline.
Looking at the torque curve, I believe it.
To me that sounds like the turbo can only pump so much air and at high rpm the boost falls off because there isn't enough flow to maintain the pressure.
If I can get a turbo that holds on to 20.5 psi until redline, I estimate a 25% increase in power from 180 to 225 whp.
If I can add more boost or find power from a free flowing exhaust, intake or upgraded intercooler, I might find 250 whp fairly easily.
The high pressure fuel pump is a Bosch and it looks like they only make one kind. The volume is determined by the number and height of the lobes on the fuel pump cam, worst case I'll need a billet cam and I'll wind up with a fuel system almost exactly like a Focus ST. I don't know if injectors will be a bottle neck but if they are, maybe the Focus ST will offer an upgrade? Focus ST fuel system supports 300+ whp so I'll be good if I can emulate that.
I figure a budget of $5,000 should get me close to my goal and even if I get stuck at 230 whp, it will still be knocking on the door of 13s with the right driver and suspension.