I had a PSS shaft seal on my 34
I had one on my 34 and installed one on my P42 this spring. In both cases I ended up with no water coming in around the prop shaft. The installation is fairly straight forward. The single biggest problem was getting the flange off of the prop shaft. Putting a socket between the prop shaft and the transmission flange and using progressively shorter bolts to pull the flange off the shaft is time consuming but will work every time. Installing the bellows is not a problem, and taking care to take all burrs off of the shaft, keyway, and shaft end will ensure that the rotor "O" rings do not get damaged and leak when the rotor is installed. I would not go any other way. Also, while you have it all apart is a great time to install a shaft saver as well. It goes between the transmission flange and the prop shaft flange and takes the strain of any mis alignment off of the transmission bearings.