What I should have added is that the six cylinder is also more flexible off turbo. The four cylinder is okay, but can be caught out if you floor it from very low (1000ish) revs. There is a bit of a pause whilst it gathers a few revs before delivering a swift kick in the backside as it heads for the horizon.
The six cylinder by comparison has noticably more shove and whilst it still needs to get up to about 1250rpm before it really takes off, it will pull reasonably well at seriously low revs.
Gone: Fiesta - Focus - E46 320dSE - E91 330dMSport - E82 135iMSport - R55 JCW Clubman
Now: M135i with lots of toys