A compressor is NOT the same as the 'modulator'.
Two different animals.
'Speech processor' = 'audio/speech compressor' = 'compressor'.
The TopGun compressor - or 'processor' - works on AM, FM, and SSB modes. It is directly hooked in to the radio's audio IC chip that preamplifies the mic audio.
The TopGun 'Modulator' works on AM only, is installed much in the same way a NPC mod is, and requires being hooked into the AM modulation regulator transistor. Works just like the NPC mod. When 200% or 300% modulation is applied to a 2 watt AM dead key with an NPC mod installed, you will see 16 to 32 watts PEP swing - respectively (Using MOSFETS transistors will allow it dead key low and swing higher with the NPC mod due to the nature of the dual MOSFET's in Magnum radios).
Or put another way:
A stock radio (w/o the NPC mod) on AM with 100% modulation will swing 8 watts with a 2 watt dead key (a '4 to 1 ratio') - as an example.
Double or tripling those PEP output numbers is a direct result of the NPC mod ALLOWING 200% or 300% modulation.
But
ONLY IF the NPC mod, or 'TopGun Modulator', or even the 'Mauldulator' (all the same thing with a different name-BTW) is installed can you get that much modulation without distortion.
Don't know about the term 'swing mod' - but as a guess - it might mean the same thing.
This should explain what I'm saying:
http://www.youtube.com/watch?v=gZDCyDNBG5k&feature=player_embedded
http://www.topguntec.com/tgt_md_1.htm
I hope that I made it understood now.
At least, that is the way I understand it.