I drove a friends decent 3.0 Elite tonight...the one I rebuilt much of the top end on last year.. it opened my eyes a bit..
Having driven nothing but V6 Omega's for the last couple of years, I must say that going back to a 2.0 16v, having had it for a short period, I am
extremely disappointed 
Yes, the 4 Pots are not bad engines.... in Vectra's. Unfortunately in the Omega, they're not fully up to the job. I wanted to overtake something this morning, I could have easily done it in the V6.. but I didn't dare risk it in the 2.0. . it just didn't have the balls...
The 2.0 is
completely un-refined, and rough, nowhere near the level of smoothness of a decent V6. The only advantage is that they are easier to work on due to more space.. but the trade-off is that they're not as reliable or durable as the V6.
Going up the road in the 2.0 this morning, first few miles from cold, you genuinely would have thought it was a diesel!!!
Insurance is no better on the 2.0 than the 2.5, and not much difference between the 3.0
Economy... don't get me started. YES the 2.0 is great on a run, returning 37mpg plus... but normal driving, it's no different, if not worse.. than the V6.
