Hi, I replaced both in a 185 I owned a few years back. Eagle suggested cutting them up to remove if I wasn't going to use them for cores or going to try to sell as cores, worked real well, just reached in through the opening in the wing and cut into strips with a knife. I will agree that the hardest part was removing the fuel softened glue/tape and installing the new tape. I set up a scaffold in front of the wing so that it was a comfortable height to work and covered the top of the wing with poly sheeting to protect the paint from the solvent I used to remove the old glue. Note do this with the hangar doors open to have good ventilation. I laid the new bladder out in the sun for a hour or so to warm it up before folding to fit through the opening in the wing. My plane had long range tanks which makes it easier to reach some of the snaps do to the two filler openings, and I still had black and blue marks on my upper arm and shoulder from forcing my arm into the opening to get the last snaps in the corners. While you have the bladder out take a look at the under side of the upper wing surface and the front of the tank bay, that's the wing spar, for corrosion due to condensation between the bladder and the skin. I have told several people that this is one of those jobs I would do to help a friend but not for money.
Just a job like anything else, have fun and good luck. Tim