I am about to purchase a -31 actuator for use on my cossie 4x4 turbo (which didnt have one with it)

I need to know if they made them with different spring ratings. My plan is to have a base setting of 14psi going up to 18psi.

The part number (garrett) that i am about to buy is 430099-0031. i have been told that they did them in 4psi, 7psi, 10 and 1 bar, bit confused to be honest and a search doesnt reveal the specific information i'm looking for.

TIA

Gareth