Jim, I found the Vetus K75 mounts made a HUGE difference in the amount of vibration we have on our boat.
How difficult you find the job depends on how willing you are to tackle mechanical jobs. On our '95 we didn't remove the galley and hoist the motor using the boom as some others have done. I found we didn't have to.
Here's what we did:
Disconnect the shaft at the transmission. We also had to remove the exhaust riser and a plywood access panel from under the galley drawers.
Remove the engine access doors on three sides. We used a 3' wrecking bar under the front engine mount flange to lift the front of the motor (it's only 300lbs). Slide the old mount out and slide a block of wood in to hold it temporarily. With the old and new mounts on the galley counter use a combination square to get the new mount set to the height of the old mount prior to installing it -- you'll make final adjustments when you re-connect the shaft. Also use a block of wood under the wrecking bar so you don't damage the door frame.
For the rear mounts a picture is worth a thousand words. If you look at the picture below you'll see a forward bolt hole in the mounting bracket. I ran a long bolt down through that hole and threaded on a nut. I bottomed the bolt onto the stringer with an undersized fender washer to protect the fiberglass. With a ratchet on the bolt and a wrench holding the nut I was able to use the bolt as a jack and raise the rear of the engine enough to swap the mount (you can't get a pry bar under the rear mounts). For the starboard mount we had to remove the transmission shift cable bracket to get the last 1/4" of height. If you do make sure you mark the bracket and trans with a sharpie to make re-installation easier.
When you're done snug the shaft flange up to the trans and follow the directions posted above for final alignment with a feeler gauge. If you were careful in setting the height of the new mounts you should already be pretty close on the alignment. The most helpful tool on a job like this is patience. Take your time, bag and label parts as you go and think through each step.
When reinstalling the exhaust riser replace the rubber hose between the riser and the water lift muffler with a hump hose. This will take a lot of strain off the muffler and extend its life. Both the hump hose and exhaust riser gasket are available from Catalina Direct. Add anti-freeze as needed. I had a friend help with this job and the extra pair of hands was a big help.
BTW, this engine is still produced by Westerbeke and the parts are readily available through Kubota dealers and through Westerbeke and its dealers.
Click Here for Westerbeke's page on the motor. It has specs and links to manuals, parts kits, diagrams and technical bulletins. You can usually connect with one of their tech reps at the Atlantic City Boat show in February or at the Annapolis show in the fall.
Best of luck,
Jim