These modified versions of the biogenerator only affect its storage capacity (i.e. 1 second of power will cost you the same amount of fuel than in the vanilla version), don't add them all, choose the version you want.
They are named accordingly to how many time they can produce power (i.e. _modifiedBioGen4s.pak will offer 4 seconds of power and _modifiedBioGen5mn.pak will give 5 minutes of power).