is there no receipts to show what owrk has been done / chip fitted etc?

generally a set of greens are speced with a 3 bar map sensor - UNLESS its the GGR setup that retains the factory escos 2.5 bar unit that runs in greens.

a loss of power at 4K sounds like its in limp mode - which the ecu drops back to to protect the engine if it detects a faulty sensor. usually suspects are lambda probe or ECT sensor. but if it hasn't yet had the multiplugs that join the car harness to the engine loom behind the passenger headlight - these can cause all sorts fo problems - most people chop them out and solder each wire with heatshrink over the top.