Here are some of the results of different server jars for mods!
Tekkit Lite: very laggy, even for just one person. It was minecraft 1.4.6
Ftb lite: worked very well, and there was no noticeable lag. Minecraft 1.6.4.
However, ftb lite had no build craft and industrial craft, so I chose not to use it.
Things I will be testing are:
Spigot + tekkit lite
Spigot + risers pack
Tell me what u think.