Hi, welcome to the forum.

What you have to consider first and foremost is the insurance and running costs.
19 years old, fast car underneath you and 18/22 mpg with a heavy foot with a 3.0. The car can be provoked very easy into wheel spin as is a big/heavy car to handle when it breaks lose. 7 mpg on the display if you keep your foot on the floor.
Personally, and from experience I would stay clear of the 3.0 with only 2 years road experience at the age of 19 and enjoy the benefits of your 150 mile trips with either a 2.0 or a facelift 2.2
At 21 your insurance will come down with a bump and with what you save there it will benefit helping with running costs.
Image, to a degree a lot might say it's classed as an older persons sort of car. but I think that is down to the individual.
Just read what Broomies Mate wrote and agree with his comments. Leaving the load pedal alone, erm, well at 19 and the way I drive I would have at least shredded the O/S rear tyre on a weekly basis and would never have seen the potential of 34mpg mpg on a run. When I was 22 I bought a Sylvia Turbo they had an 1800 4 pot with 195 tyres on, I ran it in for 1000 miles and the rear tyres were like racing slicks at 4000 miles and that only had 135 bhp plus I never mananaged more then 22 mpg after it was run in. But that was no where near as heavy and handled a lot better than the Omega. Plus it Replaced an Astre GTE which after that experience with FWD all I can say is never again.
As mentioned if you can afford the bills and insurance to run a 3.0 they you will bloody love it. Speak to Tunnie, he has a 2.2 and his Mum and dad have V6' that he uses, he may well be better placed to advise
