Paul - please don't take this the wrong way but ...... why bother owning any version of an Omega if you can also own & run an 8 series BMW? The Omega is never gonna hold a candle to the BMW while it has 4 wheels on the ground. It always going to be an 'also ran'. I've looked under the bonnet of an 850 V12 once - it was while the owner's son-in-law had been driving it .... it was ceretainly compact/frightening! 
LOL... it's not as crazy as it seems! The reason I have the Omega is that you can buy an almost top spec dual-fuel 3.0 manual MV6 for buttons (c. £2k), which does around 27 MPG on gas, compared to ~18 MPG of the BMW. Servicing is cheaper, I can rack up big miles with almost no effect on the resale price since it's lost most of its value already, it'll carry 4 or even 5 people comfortably (BMW is really a 2 seater) and I can leave it parked out on the street in the city centre at weekends without worrying about vandalism etc. The 840 is a great car in a completely different league to the Omega -- solid build, great to drive, striking looks and wonderful V8 engine sound -- but it's expensive to run and is totally impractical for doing stuff like snowboarding or going on inter-city party trips with mates.
Horses for courses, they each have their own very different merits. When I had a 540i a few years back that was a car that could pretty much do it all (although it looks somewhat bland), but I quite like the two car approach as it means I can have something a bit fancier without giving up all the benefits of a more mundane practical car. What I save in petrol, servicing, depreciation and cheaper insurance (due to limited mileage) most likely pays for the Omega anyway.