http://forums.mg-rover.org/showthread.php?t=247449
and
http://forums.mg-rover.org/showthread.php?t=351273&highlight=demon+shine
generally these types of products are crap and that is probably no exception. i dont mean to sound brutal but id rather be honest than have u make a mess of your car. like you said, it will definitly scratch your paintjob with grit but because its a silicone based product as you remove the grit with the cloth (and create scratches in the process) the silicone will fill the scratches up leaving you with a very nice shiny finish but after one or two rain showers washing the silicone back out of the scratches your car will look ultra nasty!
there is no substitute for a good wash lol... i would recommend http://www.nubawax.com/shop/article_001/IONCOAT®-NAVIWAX-LIGHT.html?shop_param=cid=1&aid=001& or choose the appropriate one from that site for your colour... its a wee bit expensive at £35.00 but it literally lasts 6-8 months between applications, looks amazing, and when it rains if the car is exposed it virtually washes itself off as the dirt doesnt get a chance to stick to the car
theres the advice you want 
