I went for the S-moto tail tidy. The good thing about it is, that the tail has some flex in it. Which is good on a mono engine.

It's design has one flaw though, which can be corrected easily. By default, the taillight is only fastened at the top. But with a few nuts, bolts n brackets from the hardware store, you can mount the bottem part of the taillight too.

I wrote S-moto about this and they would look into it. Still haven't heard from them. So far for aftersales

You can read more about this tail tidy in my topic: http://www.xt660.com/showpost.php?p=212959&postcount=34