ok well i have a 91 convertible as well, and when i ran speaker wire and a few other accessories, i had to just look around for small gaps here and there where i could push through just enough wire...you will have to take the little carpet/plastic pieces down from the inside of the trunk almost like your going for the spare tire and look through from the inside of the car in the convertible "well" area where the top is stored and you might find space to push some wires either that or you can drill a small hole through this area, be careful though you wouldnt want any leaks....
