can u turn boost up or down on 95 wrx uk

 

95 wrx uk doesn't exist it's either a wrx or UK.

You can turn up the boost but will need a manual or electronic boost controller but you need to get them set up properly (get the fuelling checked etc)

don't see why you would want to turn down the boost

 

the mbc or ebc can also turn it down

if you want to turn down a standard car then just connect the small hose from the tubo direct to the actuator.
This will then run actuator cracking pressure approx 0.6bar, instead of 0.87bar (standard WRX95 pressure)