Wow, that's some bad luck you've been having fella..
Bellows are fairly straight forward to change, but you do need to pull the drive to do as there's a big Circlip that will only go in when the drive is removed!
To summarise, with drive in the 'down' position and in neutral:
- Remove Trim cylinders from drive (just take off the Circlips and washers from each side and take them off the Stainless pivot shaft(s), you don't need to undo any pipes etc....
- Remove front panel and disconnect shift cable
- remove 6 bolts holding drive to transom shield
- wiggle (technical term, lol) drive, swear a bit and pull it off, sometimes easier with a stand/friend to help
- change bellows - The big Circlip is the most annoying part of the job! You'll need some patience and big circlip pliers.
- assembly is the reverse of removal
- have beer ready to celebrate a job well done.
I'd definitely check the driveshaft bellows too, they are more important and if those go you'll need to change the gimbal bearing too and that's more $$.
Whilst the drive is off, you'll be in a good position to grease the u-joints and splines before refitting - there are a couple of o-rings on the drive shaft and one around the water port that will need changing for new items before you refit.
The splits in the rubber say the exhaust ones are quite old and worn... the new ones may have small cuts or holes in, place these at the bottom.