To Repower or Not To Repower? That is The Question.

[ChrisG]

I have a 1976 Sceptre 23 that was neglected before I purchased it in May '03. The boat has a 1986 Commander 351ci/260hp I/O connected to the original Mercury outdrive. I just ran aground and had to replace the torque coupling. In the process I also replaced the seals and the lower unit on the outdrive and rebuilt the stringers where the engine mounts. As it sits I have about $10K in a boat with no electronics (not even a depth finder), a windlass that works sporadically, no top, a faulty trim/tilt motor and an engine that takes 10-minutes to start.
The question is should I try to restore the boat and repower or should I sell now and cut my losses? If I invest another $25K in repower and restoration will the boat be worth $35K when I'm done? If I repower, the cheapest route would be to drop in a new Mercury 350 MAG MPI Horizon @ 300hp coupled to a Bravo I or II outdrive. The other possibilities would be a Yanmar 6LPA-STZP @ 310hp I/O set up or a Suzuki DF 250hp on a bracket. I think the Suzuki will be the most expensive option considering the need to rebuild the transom and purchase a bracket on top of the cost of the engine. Considering all this, which engine package would bring the best performance to the boat and which would bring the best value?
It doesn't make much sense to me to invest much more into the boat than it will be worth when I'm done.
Any direction or advice anyone could give me would be most appreciated.
BTW: In a recent review of the Hunt Surfhunter 29, the auther mentioned three hulls he thought have been the most sea worthy on the water. Bertram 31 and the Original Seacraft Sceptre 23' were the first two on his list. Makes me feel great about the hull.