Not much mpg benefit vs. the cost of diesel. They should bring a 4 banger TDI here as well. Then you'd see some real mpg difference.
Edit...for the 3 series I meant. X5 will be to heavy for a I4.
My Original Car 335I Coupe / Space / Black Dakota / Gray Poplar / ZSP / ZPP / Step / Paddles / Nav / Hot Seats / IPOD/ Xpel HL