With this f#%king 2.2DTi

Why cant anyone diagnose accurately what is wrong with it? Very frustrated and very annoyed.... I'm very much contemplating driving it off the cliff into the quarry behind my house.
Since collecting the car off of Twiggers i have done:
Vauxhall Main Dealer parts:
Mass Air Flow Sensor
Boost Vacuum Inlet Sensor
ECU Oil Temperature Sensor
ECU Coolant Temperature Sensor
Dash Coolant Temperature Sensor
Tech-2'd by Kevin Woods
DPF Cut open, de-catted and welded up
EGR removed and cleaned
Proven working EGR fitted - No different
Entire vacuum system replaced, vacuum lines, connections, pump, solenoids
Inlet stripped down, de-coked, swirl flaps checked & New gaskets fitted
Replaced Header tank
New exhaust system fitted
Full filters & Fluids change
Previous owner fitted:
New/Reconditioned Turbo from Essex Turbos
New/Reconditioned Intercooler
My last option was the ECU, spoke to
www.the-ecu-doctor.co.uk this morning and they are saying it will need a new board at the cost of £295!
I suppose i'm just looking for advice now, I can't break it as i just don't have the space or time and i can't sell it

What to do....?