I'll be getting a fresh rebuild soon and I'm worried about the break in period. Is it possible to get a manual boost controller and set it for like 1 psi or something, or just find a way to wire open the wastegate? stock s5 turbo

 

For about the billionth time boost controllers can't lower boost! Do not install a boost controller at all until the motor is broken in.

Wiring the wastegate open will make boost biuld much slower, but if you leave your foot down you will still reach max boost in higher gears. It's still entirely up to you to drive the engine sensibly until it's properly broken in.