Depends on how much "cowboy" you want to do
You can turn the pump up
a bit, which may give a little bit more poke depending on what the state of tune is like just now. Some would say soong as there is not clouds of black smoke then it's fine, but that is NOT how to tune a diesel properly!!
TBH you will only get marginal improvements without sticking in a bigger intercooler. Check that the one you have is clear of oil and gunk, flush it if necessary. Condition of the turbo hoses is also very important, they are prone to collapsing internally when under pressure due to age.