Assuming you have a good solid engine and box to start with, you have a few options available to you depending on finance.
Uprated intercooler and silicone hoses will give a healthy boost with a good chip.
With regard to the turbo, depends on knowledge and bravery.
If you want to play with boost, first, get a boost gauge and exhaust gas temp gauge.
Next you can either use the adjuster built into the wastegate actuator, or a boodt controller. Bare in mind though that the map sensor is limited to 18psi, map sensors have been changed by jeremy fearne but I have no idea what type was used.
From net research, if adjusting the actuator rod, each turn of it roughly equates to 0.1bar+/-.
From there you can uprate injectors and so on, bjt really. What's the point.
Good luck. But to be honest, trade the beast in for a v8.