Turbo is the way to go if you want to hit that mark. Also save some money to the side for when the tranny goes (if it’s high mileage), big brake kit, suspension (if you don’t have any you will need it) also exhaust it’s needed to maximize horsepower. You may want to do a leak down and compression test just it case because as soon as you are at full boost and you have a compression issue say goodbye to the motor
Its all about rolling in the X5 !!!