I drive a Diesel as well. Same configuration as yours( 2.5 Tdi AKE(180 PS) 6sp).
Prices that you give, sounds real. But don't worry about turbo. If u will care for it( don't switch off the engine streight away, leve it for 20s - 30s too let the turbo cool of) shuoldn't have any trouble...

"oil filter housings cause major crankcase pressure problems (£400+), which make for lost of oil leaks (£200-400)"

All road has the latest engine which don't have that problem. Just use good 5w-40 oil and enjoy the 370 Nm...
In england you can chip'ed that motor to very healthy and safe 205 Bhp or 225Bhp.