Easiest way I found to fix these buggers was to make them someone elses problem!
Take the car to an auto-elecrtician and ask him to install something a bit more modern (ie code for cheap but works).
These guys usually have couple to choose from at reasonable prices so long as he installs it.
That way you still have an alarm/immobiliser to keep the light-fingered at bay, the wife will still talk to you and you don't have to spend Christmas under the dash praying everything will still work in the new year!
Good luck which ever way you plan to go.