I know this is an old string but I am a new member and I wanted to comment about Swim Platforms, Inc.
I have an '89 340DA. The original platform is only 22 inches front to back. I needed a bigger platform and looked everywhere. We never used our transom door to board, our dogs kept falling off, it was practically useless.
I sent an inquiry to Swim Platforms, Inc. with a picture of our boat and got a return email the next day with prices. I then get an email from Scott Samuelson, the owner who informs me i own his old boat. He recognized it from the pictures and told me the story of ordering from the factory while he was an employee.
We bought the platform and had it installed and what a difference. the new one is 39" front to back, fit perfectly and has changed the way we boat. When we stearn in at marinas, everyone wants to know where we got it and because it's so big we can put deck chairs on it an sit and watch the fun.
For anyone that is contemplating a new platform, you will not go wrong buying from them.
PS The dogs still fall off so I guess it was the dogs and not the old platform.