Hi there,
I know there are people who despise cheating. Everybody can have her or his opinion. Don't hijack this thread if you oppose my view, try to resiiiiist the urge. :)

Anyway, for everyone who just likes to play this game again after many years, zen-like without hassle or pressure, there is a way to circumvent the cheat penalty you get when activating invulnerability or unlimited weapons.

The follwing only works for the 93 DOS version (afaik). I'll try to walk you through from step one.

1. Install the GOG DOS version into a folder on your hard drive which doesn't contain any funny letters, blanks or special chars/umlauts or anything. Something simple like c:\XWING is preferable.
(There are several reasons for this, among them the fact that DOS can't deal with file or dir names which contain funny or too many letters).

2. Get this: http://www.rebelsquadrons.org/xwing/files/xp/xp152.zip
It's an editor which works for X-Wing, Tie Fighter and various addons. But it only works in DOS.
Copy the contents of the zip file into the root folder of your X-Wing installation, in my case it's c:\XWING

3. To start the editor you could probably use the dosbox version that comes with X-Wing, but I use a separate dosbox installation. Get it here and install it anywhere you like (on the same computer on which you have X-Wing, of course)
http://www.dosbox.com/download.php?main=1

4. Start doxbox and mount your c: drive, like this:
mount c c:\

5. Take a look at the manual for X-Wing Editor Pro, to understand how this editor works and what it can do. Manual can be found here:
http://www.rebelsquadrons.org/xwing/files/xp/xp.txt

6. Switch into the X-Wing directory and start the editor, like this:
c:\XWING\xp.exe

7. You get a screen with a menu which contains 5 options. One of them is called "Other X-Wing Stuff". Use your cursor/arrow keys on the keyboard to highlight it and hit the ENTER key.

8. You get another menu with several options. One of them is called "Disable Cheat Flag". Again, use the cursor keys to highlight it, hit ENTER. Hit ESC to get back to the main menu and leave the editor.

9. You're done. You can complete missions now with cheats enabled, getting all points, rewards, promotions etc. Close dosbox and fire up X-Wing using your regular GOG Desktop shortcut.

Have fun!

Thanks for this.
I have gone thru the game a couple of times without cheats, but this will be useful for debugging some custom missions and tours of duty. :)