But a tune, like Trifecta comes in levels does it not? Pre-programmed to give the 1.4 a known range based on engine parameters set by the new tune.
The tune has a lot of parameters. Way more than you're probably thinking right now; I know I was quite surprised to see them all, and that's with already having researched the tune fairly extensively before beginning to tune mine.
When you press the gas pedal there are probably at least 4-5 tables the car "looks at" before it determines how much boost and power to give you. There are lots of ways to limit what your final product will be at the tires.
Just a few off the top of my head that could limit commanded power:
Max boost limit, brake torque limit, peak torque limit, trans output max, axle torque max, driver demand, traction control, rev limiter, speed limiter, pressure ratio max, base wg duty cycle... it goes on an on.
A properly tuned car will make good and smooth power with reasonable boost levels. 180whp seems to be what BNR advertises for 93 octane, 200whp is what they advertise for e85. I think it's safe to say that both of those number are the upper spectrum of what you can expect. I haven't dyno'd but I'm probably at 140-150whp and who knows what torque, spooling to 18psi and tapering down to 15-16 by redline, and it is a hugely different car to drive at wide open throttle.
What I'm trying to say is this: don't pick a horsepower number out of the sky and get hung up on it. You would be surprised how little it takes to make a big difference.