hi...
Congrats on the 330D...
Whats the mileage on the motor..and has the Turbo been changed on the car...
I am sure that you can get some huge gains with S/W, and DP... and because its a manual, you should not have the issues with the gearbox getting eaten up with all the extra torque...
The issue with adding software is that it might place additional strain on turbo... though a properly designed map should not cause too much damage to the turbo...
It might make sense to replace the turbo and then remap the car. R10k for Turbo and whatever the tuner charges... will be a great investment in the power, plus the reliability of the car.
just my R0.02