FFRR Modelyear/engine recommendations

[Role]

Looking to buy a FFRR, expect to do 15k miles/yr.
any recommendation as to year and engine?
I understand 2006 saw an update. Is it much better then 2004/2005 models?
R

[kVA]

Oh yes...

New engine and gearbox (petrol) - Supercharger available. New Sat Nav, Audio, etc... New seats, climate control system and a few other bits.

Diesel engine unchanged though until 2007 MY, but boy was that a change! Straight six noisy, gutless BMW lump changed for TDV8 twin turbo unit with 640Nm of torque!