Can anyone tell me what the Maximum Safe Boost on 01MY WRX is.
I have recently had a Superchip fitted and boost is fluttering about abit.
I also have GGR K&N Cone filter.

 

I thought I came across something that said it was 1.4 bar but i can't remember where i saw it I'm afraid

 

I would doubt there would be sufficient fuelling for 21.5 psi (ish).

I would say 18psi (ish) would be towards the upper limit without fuelling mods.
Be careful!

 

With the original turbo, plus a decat exhaust etc, about 1.2 - 1.25 bar is as high as most TEK'd ones etc are mapped to, I wouldn't aim for more than that. You might make 1.4 with a very well sorted car runnning a standard turbo and an uprated top mount intercooler due to ~2psi less pressure drop across the intercooler.

1.4 is common with a bigger turbo, which will usually be accompanied by an uprated fuel pump and regulator, and quite possibly injectors too.