It's pretty straightforward.. did it on my Reference Sport in about half a day - have done it a lot quicker since now I know what's what.
They're held in place with 'star-head' screws around the wheel arches, along the underneath and the top edge each. The rear bumper requires the removal of the rear light clusters (2 bolts on the pillars and one from behind in the bulb access bits). The edges of the bumpers (where they meet the other panels) can be tricky as the clips are tight - they just require a really good solid pull outwards away from the body.
