Not necessarily. Increased boost does increase the airflow, which is more important. But if there are a lot of restrictions or chokepoints in the turbo or intake plumbing, this will create heat, BAD for your engines! It's best to minimize pressure loss by upgrading all your turbo plumbings, especially if you want to boost past 1.5 bar for a stock-engine EVO. Again, I have a friend who upgraded his entire plumbing just because it looks cool though he can't boost past 1.05, maybe 1.1 bar if he's lucky because he has practically no pressure drop or loss in his plumbing system.
I have a similar situation to your mate.....
I have the Mines alloy boost pipes to and from the intercooler and a free flow APEXi induction kit which is fed from a rather large flexible hose which blows air into the system from near the brake cooling ducts. I can peak upto 1.4 bar using the Blitz DSBC but cannot sustain much more than 1 - 1.05 bar pressure. The car seems lively enough since I cleaned the induction filter (it was getting rather blocked after 8000 miles) I would ideally like to peak at 1.15 bar and sustain 1.1 bar but this doesn't seem possible. Are there any other restrictors fitted apart from the grommet ?
I don't use the standard solenoid and grommet as my boost controller has its own.