I like the space in x5, but the consumption must be doube probably also the speed will suffere

why do you folk condiser buying x5, is it the room, children, family...

1000 lbs extra never helps performance or mileage. But there is more useable space and ground clearance (for winter driving). We looked at both and my wife wanted the X5.

The X5 will be available with diesel soon in the US. If you drive long distances it may make sense. It used to be that you had to pay maybe $3000 for the diesel option on a car or truck in the US and that was the only expense you have to make up in better economy. Now you also have to pay 20% more for diesel fuel. If the diesel gets 30% better mileage, how many miles will you have to drive to make up for the diesel option price?

Savings per 10,000 miles if gas gets 20 and diesel gets 26 mpg. Diesel uses 385 gallons at $4.60 for a total cost of about $1765. Gas uses 500 gallons at $4.00 for a total cost of $2000. Difference is $235 per year. Spend $3000 for the diesel option and it takes about 12.5 years to make up the difference.

Play with the numbers a bit if you like. Unless fuel prices skyrocket, you probably won't do that well with the diesel unless you keep the car for more than 8 years or drive it more than 100,000 miles.