I've done it with the rack in the car, it's just a little more of a PITA. The boot does need to come off since you need to slide it onto the new tie rod. Once the boot is unclamped, you slide it as far to the outside of the car as possible and then follow the instructions below. Don't forget to hold the steering rack with one wrench while you turn the old inner tie rod off. You may find that to get the old rod off that it's easier to get it turning if you unbend or grind away the part that's been staked to the rack. If you grind them off, be sure to mask the rack so as not to get metal filings in the housing.