Do I have to remove the subframe to replace a.

Don't even waste your time attempting this unless the car is up on a hoist. Warranty pays 3.5 hours and it actually takes a real lot longer if you never did one before. The cross member has to be lowered about six inches to get to the mounting bolts for the rack but the pressure hose will only allow it to be lowered one inch. The secret is to remove the left front wheel, then use a crow's foot wrench, two extensions and a swivel to loosen the hose, then drop the cross member.