I would go for an Omega V6, preferably the 3.0 or 3.2. A very nice place to be for a motorway journey and the interior beats the spartan 5 series BMW.
Go for an Elite for all the toys or an MV6 with slightly fewer toys but slightly sharper handling.
You get a bonus every time you open the taps too - especially with a drilled airbox. There are few better sounding V6s.