Man, you can do a lot to a CRX with 10 grand. Ok, first thing I would do is get the rust taken care of and get it repainted the OEM black (oh, I love it, looks red from the side...). Next would be the interior, really just the driver's seat being a little soft, get it restuffed with brand new foam and get a new carpet. With it more or less back to stock, I would hire a team of professional scientists from Honda with labcoats and/or clipboards to track down and eliminate the water leak in the hatch. This alone may cost over 10,000.