I came from a diesel too. I'm spending lot more time on petrol station forecourts now!
I've been driving in Manual mode a lot lately as I've gotten to grips with it now, and I dont seem to get better than 18mpg. Worth it for the blips on the down shift though!
And I agree with the modding, with loads of toys as standard and little to be gained from the engine without spending silly money, there's arguably very little to be done. A few choice chasis mods are all I'm planning for the time being.