Had a look at the exhaust db register and the Motoria is louder than the Nur Spec!! That's quite a big factor for me as when I 1st started looking into zausts, I was worried that a Nur Spec would be too loud!!
Budget wise, I've not really got one, BUT the cheaper the better!! I've got £750 spare and the less I spend on an exhaust, the more I have for something else!! Perhaps a filter!? Looked at getting the Whifbitz exhaust and filter package for £570 but I'd need to confirm that price because if you buy the pipe and filter separately from his site it works out around £540 so there must be a typo somewhere!