[Tambohamilton]

No experience of petrols, but can vouch for the 6 pot diesels being night and day with the 4 pot. Partner has a N47 118d, which is shaky and pathetic until 1800+rpm. My M57 330d (OK, a number of rungs up the ladder from the 118) on the other hand runs so much smoother, barely any clutch/dmf judder, and has heaps more off-boost torque. 118d will do 50mpg without trying though, where the 330 averages high 30s to low 40s...will do 45 mpg on a motorway run.

I did the chains on the N47 myself...not a fun job! 330 sips oil, but not enough to cause any worry. I trust both fully in terms of reliability, but will always choose the 330 for a trip, despite fuel costs.

The 330 is generally more reliable than the 4 pots partially because they're lower stressed to produce their peak power, and I think partially because they have so much more low down grunt you don't need to rev them hard to get about.

All that said, does anyone need any more car/performance than a 320?

YMMV, etc