TDM is the initials of the three main creators of the modpack.
TCP? as in TCP/IP? or something else?
The ultimate mod is the one "you" create by merging the best parts of everybody else's.
Everyone has their own "ultimate" mod, since everybody has a different view of what futuristic space empires and battles will be like.
A good idea would be to take everybody's mods and pull out the smallest blocks of changes, then post 'em all as a mix&match modpack.
Then only basic mod skills are required to build your own personal Ultimate mod.
"Hmmm I'll take some ablative armor... those PD missiles look cool... I'll take half a dozen of these crossover components... gimme all of those extra events, and throw in one of those battlemoons 
"