I love my 07 reg Vectra sri cdti 120...
It's doing a minimum of 600 miles to a tank, I've seen 900 miles on the motorway, I'm sure it'll do 1000...
I'd recommend the 8v 120...
Just do your research on them...
I bought mine cheap knowing it needed some work...
But mine had recently had new alternator, dmf, egr...
So mines mainly needed service items...

Some 150's have a dpf!!!
Along with the dodgy inlets I'd get a 120, remap it and enjoy...