Determine which 25 foot Tanzer the boat is. There were two.
One was actually called the Tanzer 7.5. It looks somewhat similar to the Tanzer 26 but is not nearly as robust a boat as the 26 as it is built on a much smaller hull - it does however have a nice amount of interior room.
The second was actually called the Tanzer 25 I believe. However I think that was manufactured in the 80s near the very end of Tanzer production. It was a very nice boat and quite fast. It would sell for a much higher price than the Tanzer 7.5