Hi Mr L - Ditto what Audax says in both posts. And the V6 has more oomph than the diesel alternatives you were considering.
If you (or SWMBO) drive the V6 like you drove the 1.8t, you shouldn't see much worse consumption. I did 60k in a 2.0 Citroen Xantia (120bhp), 60k in a Galant 2.5 V6 (163bhp), 10k in a 9-3 2.0t (175bhp), and now 85k in a Hirsched 9-5 2.3t (220bhp), all autos, and while consumption per tankful varied between 22 and 35 mpg for each, over all those mileages all four gave around 26-28mpg.
Every now and again the performance just has to be enjoyed, but in normal driving (whatever that means) a V6 shouldn't make too much strain on the wallet (or purse).