Originally Posted by Stu @ M Developments

Correct.
Do you guys twiddle your fuel pressure regs too?

They do remove the ecu's ability to lower boost if you actually replace your boost control valve with one instead of fitting it in adition to it, but they are no more dangerous than an amal valve providing:

1) You use a quality one like this:
2) You set it safely, which usually means letting a tuner set it.