The unit come from Rhencullen, and cost £146 painted (approx. £80 unpainted). They do a few different kinds, but this was the easiest to fit and does not need to have the bottom of the tool box (storage area) cut out - for me, that was a major bonus. You can also get built in indicators that fit into the vents in the seat unit (see photo above) for the extra stream lined look.
Some of the other undertrays need the bottom of the tool box to be cut out. It will involve a bit extra work, but will give a cleaner look - try this one - prototype just now.......
The above picture tell the story - before, during and after.
Quite easy really, but it is a one way modification - no going back. I guess if you want to push it, you could do it in about 1 to 1.5 hours. I took it easy at 4hours - but, that did include making the combined indicator / number plate holder from scratch.
First, you take the old number plate, holder, indicators etc off. The cut the rear mudgaurd flush with the bottom of the tool tray - an ordinary hacksaw will do the trick. There is also a securing point for a strap that has to be removed as well as cutting flush a drain hole.
After taking of both seats and the loosening the tail unit, the undertray justs slides in. Dead easy. As I said before, the most time consuming bit was making the combined number plate / indicator bracket - it took me three attempts to get one I was happy with. Homebase supplied a nice bit of aluminium which was bent to shape and drilled.
Thats about it really, nothing difficult. Judge for yourself, but I like it. In combination with raising the rear end (fitting shorter tie bars) it certainly does make the back look very clean.