This is a small tool I use, not for editing, but for playing. There are just two things I can not stand in doom.... the plasma gun sound effect and the bright white invulnerability palleted. 

This takes a input.wad, and a source.wad, then creates a new wad with just a colourmap in it that is a copy of the input.wad, but it copies the single line 32 of the colourmap that controls the way invulnerability works from the source.wad

Effectively you can copy any invulnerability colour from any wad where you like the look of it, into any wad you are currently playing, without effecting the existing colourmap. If the input.wad has no colourmap you need to supply the --iwad.

It actually saves it as a new wad, so there is no alteration to the input.wad.. add it to the load order.

Like other scripts there is an alias variable at the top for the iwads, as well as for any colourmaps you may like to use...

examples of same command one with aliases:
 
addin hiviz.wad eviII -iwad doom2
addin hiviz.wad c:\download\Eviternity-2.wad -iwad c:\doom\doom2.wad

 
Output : hiviz-invun.wad (that you can add to the end of your load order)

=========

addInvun — swap the invulnerability colormap row into a WAD COLORMAP

USAGE
  addInvun input.wad [source.wad | alias] [--iwad path|alias] [+2ndary]

WHAT IT DOES
  Copies row 32 (the invulnerability map) of the source WAD COLORMAP
  into the input WAD COLORMAP — the lighting rows (0-31) are untouched.
  Writes <inputStem>-invun.wad (PWAD) next to the input WAD, containing
  only the patched colormap lump(s).

ARGUMENTS
  input.wad        WAD whose COLORMAP is used as the base.
                   If it has no COLORMAP, --iwad becomes required and
                   supplies the base colormap instead.
  source           WAD (path) or alias providing the invulnerability row.
                   Aliases: grey, brown
                   Default if omitted: brown

OPTIONS
  --iwad path|alias  Fallback base colormap when input.wad has none.
                     Aliases: doom, doom2, tnt, plutonia, heretic, hexen, free1, free2
                     Bare --iwad uses the default: doom2
  +2ndary            Also patch every secondary colormap lump found in
  +secondary         the input WAD (any lump of exactly 8704 bytes that
                     is not COLORMAP, e.g. BLUMAP, REDMAP) and include
                     them in the output WAD under their original names.
  -h  --help  -help  Show this help.

EXAMPLES
  addInvun mymap.wad
      Patch mymap.wad COLORMAP with the "brown" alias invun row.
  addInvun mymap.wad grey
      Use the "grey" alias as the invun source.
  addInvun mymap.wad D:\wads\custom.wad
      Use an explicit WAD as the invun source.
  addInvun mymap.wad grey --iwad doom2
      mymap.wad has no COLORMAP — take the base from doom2.wad.
  addInvun mymap.wad brown +2ndary
      Also patch secondary colormaps (BLUMAP etc.) from mymap.wad.