at what RPM is max line pressure achieved?

You mean like the blue wire mod? what rpm do you achieve max pressure. All the time, one you have full line pressure, you have full line pressure.

But do not shift into first gear while above 5 mph because u will chirp the tires. I learned that the hard way, so please dont try that.

lets say your your full line is 180psi. how low of a rpm can it reach that 180psi? can it do it at 3000rpm or maybe even 2500rpm? or can it do it even lower?

Again, as far as I know full line pressure is full line pressure. So to answer your question again, u have full line pressure at any rpm is how I understand it.