Well, adding ships to SFC2 isn't too hard. You first have to open the shiplist.txt file, and I recommend Microsoft Excel to do it, as it seems to give the best results (no screw ups). Figure out where on your hard drive you want to put your new model, add a line in the shiplist.txt file and in the column where file paths are put, type in the location you want your model to be on your hard drive. Then look around the file a bit and copy the weapon, etc. spec you want and paste them in the correct columns on the line for your new ship's entry. Save your shiplist.txt file. Open up the directory where you wanted your model and copy or decompress the files into there. Make very sure you spell all the pathnames and filenames correctly or the game might crash when you run it. If you get a black screen instead a beautiful starship, chances are you either typed in the path/file names incorrectly in your shiplist.txt file or stuck the model in the wrong directory, in which case you'll have to look for it and make the corrections either to the shiplist or move the model.
Have fun blowing up the empire of your choice... if they don't get you first.