Hi
If its any help, i have dug up the initial thread one this started by ENZ525 who had the system fitted.
http://www.sportsmaserati.co.uk/showthread.php/329-Larini-Exhaust-with-Sports-cats?highlight=exhaust
The exhaust note is barely a murmur at cruise around 70-90 mph bracket inside the car. You get a very enjoyable drone if you accelerate further and when the car settles back to cruise speed there are the usual pops and bangs from the wasted fuel
before settling back to the normal.
I ferry my 5 year old kids and Mrs in this and it has not ever intruded in their going to sleep or us having a chat.
Also, the noise sealing on QPs is very good.
Done properly, this system will make the QP a car you will cherish for a long time.