LOL that's the place I used last (my dad used to use that shop a lot). I think they charge $10 a rotor last time, but that was on a afternoon Saturday.
2x 12psi = 24psi
You'll have to go custom manifolds to get what you want.
Or you can save a heap of money and go for a stock sized turbo, exhaust and tune for the same/better result.
Where did you get them done? I remember once I paid SIXTY DOLLARS PER ROTOR for my R31. Shame I had to get it done on a Saturday and the dude was close to me. I was desperate to get the car running (work reasons).
I bought brand new rotors for $60 each a year later.
Do you need a large car? How much are you intending to drive it?
I was in a similar situation, picked up a nice N16 manual ST-L for ~$5k after rego-ing it.