I installed a Kohler 5ECD in my 2001. It was pre wired from Tiara which made it not so bad. Tiara was very helpful with any questions and also providing the parts (breaker and slide lockouts for the panel.
It's installed between the engines towards the aft section. I could send you pics if you like.
The factory offered a Westerbeke 5.0KW Generator as an option (gas or diesel depending on engines). It was installed center aft between the engines mounted on a support board attached between the stringers. Engine mounted towards the bow and power generation unit mounted towards the stern. If you do install the generator there, make sure you install Spray shields over the shaft logs. Dripless shaft logs do sling a fine mist of saltwater where the seal faces come together and this would line up perfectly with the generator. The spray shields will keep your generator from becoming a ball of rust in the future.