Here's a view from the side,showing the box and bars: the wind noise was no problem except on very long, straight stretches of road when an odd, musical whistling occurred for a short period (seconds) now and then, especially in the windy areas, and if my speed crept up a bit high.....will look to sealing any gaps under the bars (there are slides cut in the underside of the bars for adjustment). This pic also shows the demountable towhitch in situ - I've bought a Lynton Loadtrekker trailer which will be delivered later this week, and as I've never used one of these hitches before (had one fitted to my 3.0i but never even plugged it in before part-exing for the 4.8
), I thought I would give it a go and make sure it all worked before the trailer arrived. With AUC checks being of dubious quality these days, I wasn't taking any chances. No worries, though - both keys present, both lock caps, the plug for the bar when the hitch is demounted, the electrics plug, and even a BMW towball cover was all stashed in the rear. Towbar itself looks like its never been used. Pity it wasn't in place when we were shunted last week!!! PS there are no starnge marks on the side of the X, its just the reflection fro the silver baby Merc standing alongside it, glinting against the sun...
Here's close up of the hitch in situ for any new X5 owners who have never seen it in use....
it took a bit of puzzling out and some online research on Westfalia's website to work out how to attach it... 
: Now that its there it can stay attached till I've moved back home!! 
I love this car, it's a blast to drive.... 