Coming from a fairly stiff FWD car, you may find the Elite quite soft (RWD doesn't need rock hard suspension to get the power down), which may take some getting use to.
Fuel aside - I get 23mpg from my 3.2 Elite and about 25mpg from my 3.0 MV6 (both autos) on petrol (about 20% less on LPG) - I've found them quite cheap to run IF you do your own work. Garages seem to struggle with them, and end up charging a fortune for substandard work.
I drive mine quite hard, so do have to take the hit on tyres and brakes, although, as mentioned, with 'trade club', service items like brakes are dirt cheap for genuine Vauxhall parts.
You don't list your location, but if you are near me, pop over, and I'll happily show you my pair, and point out their many strengths, and their weaknesses (wishbone bushes and cam cover gaskets!).
But, a 1.8t car is never going to match your FR for economy.