Very large magnetoresistance discovered in single crystals of the ferromagnetic Fe-intercalated transition-metal dichalcogenide Fe0.28TaS2 was attributed to the deviation of the Fe concentration from commensurate values (x=1/4 or 1/3), which caused magnetic moment misalignments. Here we report a study of FexTaS2 crystals with 0.23≤x≤0.35, demonstrating that crystallographic defects lead to spin disorder, which correlates with magnetotransport properties, such as switching magnetic field HS, magnetoresistance (MR), and even zero-field resistivity ρ0 and temperature coefficient A in ρ(T)=ρ0+AT2: The ordering temperature TC and Weiss temperature θW are maximized at the superstructure composition x=1/4, whereas Hs, MR, ρ0, and A are minimum. Conversely, at a composition intermediate between the superstructure compositions x=1/4 and 1/3, the corresponding magnetotransport properties reach local maxima.