I have mounted these and will share my experiences

Communication has been clear and easy
Delivery: A few days (UK to Denmark, not that far)
Finish and initial quality feel: A+++ Really nice
Fit: Good. SP has made a joint where the centre box used to be, this makes it possible to rotate the 2 ends of the pipe relatively to each other. A good idea, when you fit a new pipe into existing exhaust.
Problems: My LH pipe from downpipe to SP pipe has come closer to the heat shields and creates some resonance now. I hope to solve it by taking the rear parts apart and aling things better.
External sound:There is more. Not surprising. There is a deep rumble in idle, only 3-5 dB louder than before. Take a listen to the videos to get an idea,
Interior sound: There is more, but not much. You hear a lot more rumble at low speed, but it fades out to almost normal level at cruise speed. At 130+ kph there is more noise as well. Again: View the videos.

 

Sounds PURRRRRRfect! Just how I imagined a V12 to sound...!

Should sound awesome with all the Simply Performance exhaust parts I am getting sometime

 

That sounds assume indeed.... need to start saving.
Will not be for a while in my case, where are the kids bank books!
No cost on their website.... what are these worth?