I know exactly what you mean Tunnie.
I was in the EXACT same position as you.
2-3k Miles a year, my car was a little tired (very good example with nothing 'wrong' just tired), I was getting itchy feet and fancied a change.
Mine was a 3.0V6 Elite, and I loved it dearly.
I swapped it for a E39 V8 BMW and even though I honestly, truthfully miss the Omega, I cannot compare the two cars from a drivers point of view.
Yes the Omega had more toys, it was more comfortable and had a bigger boot with folding rear seats. The BMW has a reasonable boot (2 sets of Golf Clubs) but no folding rear seats so nothing 'big' is going in there.
It's just listening to that V8 (which you need the window down to hear as the car is so well insulated) and being much more confident that the car WILL go around 'that' corner which catches us all out at times.
I dont love this car like I loved the Omega and if I had £500 to make the Omega perfect, I probably wouldn't have swapped, but for me, it came at a time where the time or money wasn't available to sort the Mig out.
I have no regrets and I dont spend any more time at the Petrol Station. I have an extra 40BHP, an extra billion ft/lb of Torque, an extra gear in the Auto Transmission and I get called a cock a lot.
Whatever you do, do it because you want to and not because you feel you have to.