This might work for you; rather than alter the appearance and sound of the late game weapons (which would probably require .exe changes, or recompression of the game's textures, or similar nonsense), instead alter the damage values of the early game weapons to match the aliens (which can be much more easily done using the text-based .ini file). Someone requested the plasma damage values for the modern-day ballistics here: http://forums.nexusmods.com/index.php?/topic/810290-firearms-improvement/ If you want to simply keep pace with the aliens (I presume you do), alter the values to match those of the laser weapons at first, and later do what is suggested in the thread whose link I just posted. Hope that solves your issue