I have recently purchased an 8.7, which is a very similar design. I can't help you with the rudderstock problem, since mine has not required any attention. I would disassemble the halyard
winch and see if you can salvage it. You may just need to lubricate the bearing and clean the pawls. Spare parts are available on the internet. Although I have two halyard
winches, I've found that I can raise my 170% Genny without the
winch as long as I'm pointing into the wind (and it's not really blowing more that 10 knots).
Detailed information on your boat can be found at
Columbia 8.3 Specifications
I have a propane force 10 Cozy Cabin heater. The unit works great and takes the chill off the cabin when outdoor temps are as low as 25 F. However, there is no convenient place to store a propane bottle, so you may have to hang one on the stern rail. The Newport model is a nicer unit and will look great in the main Saloon. My heater is mounted to the forward port bulkhead in the saloon and the vent pipe runs through the bulkhead and up on the head side of the bulkhead. This arrangement warms up the head nicely, but you have to be careful not to get singed on the vent pipe when you have your pants down!
The previous owner replaced the aluminum tank with a plastic model. A 15 gallon tank can be guided through the cockpit locker and mounted on the original tank platform (on my model). I don't remember who built the tank, but it was not a custom unit.
I have a doger installed, but no bimini. Mine was put together by a local shop in Seward, AK, and it looks pretty old.
I've found the boat to be a suprisingly good performer and really stiff. I'm not sure what it would take to put the rail under, and I don't really want to find out.
Erik