if you look through some past threads you'll find my, and Kitch's experiences with undertrays, we both bought ones from germany and weren't impressed with the fit, i think they might be for racing bikes where you might take the rear light off.
i cut up my origional undertray to make it fit the german one, then bought the skidmarx one and a new origional from ebay for about £20 and cut this one up taking more care the second time...
you only really need to trim the flap at the back where the reg plate goes, this bit needs to come off completely, and also the corners of whats left to allow the new one to fit over it. i routed my indicator cables through the holes that the corner removing left. the instructions that came with the undertray were reasonably clear as to what to remove and a dremel took it off no probs.
only prob i had was where to mount the reg plate, the bracket they gave me was crap and not wide enough to mount it where i wanted, so i drilled two holes for the plate and mounted it directly on, and also my alarm light and a new reg plate light.
it fitted perfectly all that I needed to do was trim the pointy cornered parts at the back to fit the rear light correctly (maybe down to the fact I have fitted an after market LED rear light though). You get an indicator support with the undertray however it was just a bent piece of ally so that was scrapped and I just drilled through the side of the undertray where it's triangulated for the number plate mount (unlike the ones from Germany or Portugal it has a surface for the number plate to mount to), then double sided tapped the number plate on. The hole was pre-drilled for the seat lock barrel and you get a good fitting kit with it, although the instructions weren't that clear it's not a bad job at all and took about 2 hours taking my time. I did have to cut down the original tray just behind the tool kit part to fit it.
