Where the tridion at the back of the roof meets the sides, there is a small gulley each side.
Because there is a slight amount of movement, the paint in the gully splits. Some people
complained and smart did what they normally do, instead of fixing it, they hid the fault.
Smart doesn't like to be sensible with colours however. Examples being: even if you have a silver tridion, you got black roof bars. If you had a black coupe you would get no other option apart from silver boot hinges. To carry on from this trend, smart covered the cracks up with a black sticker.
This is the area that cracks. This one hasn't had the smart "fix".
A closer look, yep, cracked, no surprise.
Take a small strip of vinyl in your favourite colour...
...peel off the backing and apply.
Yeah, doesn't look the best but I did it in minutes using scissors in a car park whilst waiting for someone to arrive. (yes I really do take stuff with me to do How2 guides should I get the time).
I'd recommend cutting it straighter with a ruler and knife and cutting the strip
thinner to fit in the gulley, that way, any colour difference will be negligible.
The vinyl I used was silver by a company called Aslan, you can buy it in small quantities here. http://www.mdpsupplies.co.uk/
Most gloss black vinyl will match fine and this particular silver was a good match.
You could even try some of the 3M Di-Noc carbon fibre look vinyl which
can be bought in small sizes (although not necessarily cheap) off of eBay.
Of course, you could always get the official stickers from smart.