Max boost can only really be judged at full throttle .
Put it in 3rd or 4th and from 30mph just full throttle it to 5k. You will then find out what peak is.
Connect the boost guage to a vaccuum on the inlet manifold area. T off the fuel pressure reg feed Or there is a spare blanked off feed on the bulkhead just above the brake and clutch master cylinder,
There are not any benefits from going above 12psi on the standard turbo. It will just kill it for the sake of about 8hp when turbo cold
Get some proper springs made up. Chopped ones are horrid
