you're widening it 3/4" total. as long as you do the same thing to both the left & right sides, you won't cause much of a problem, however, you should check for tire clearance at the fenders, and mention what you've done when you go for wheel alignments. I personally would widen both the front & rear, but citroen has made a number of cars that had a narrower track at the rear than the front which drove well.
