The ornamental design for a vehicle side panelprotectingunit, as shown and described.
FIG. 1 is a front elevation view of a vehicle side panel protecting unit showing my new design, wherein the portions in broken lines are for illustrative purposes only and form no portion of the claimed design;
FIG. 2 is a rear elevation view of the vehicle side panel protecting unit;
FIG. 3 is a side elevated view of the vehicle side panel protecting unit, the opposite side being a mirror image;
FIG. 4 is a top plan view of the vehicle side panel protecting unit;
FIG. 5 is a bottom plan view of the vehicle side panel protecting unit; and,
FIG. 6 is a front perspective view of the vehicle side panel protecting unit, wherein the portions in broken lines are for illustrative purposes only and form no portion of the claimed design.