i have an 06 GT not comp g. im trying to find a transmission but every tranny i find is for the nonSC... are they the same? and will the 05 and 04 trans work? also someone told me about a trans 4 speed 4t65e m15 gm option code f83 3.05 ratio....

what is the m15?
what is the gm code f83?
and whats the difference in all the other trannys and the 3.05 ratio?