HKS catback

hey everyone...
 
i want to do a Catback exhaust on my car, and the shop i buy my aftermarket parts from suggested the HKS catback exhaust system.
 
i was just wondering if anyone here has this catback, or knows of someone who does.....
 
im getting it for $800, (cdn) and im installing it myself.
 
i just want to know how loud it is.. cuz im come home alot pretty late, and i dont want to wake everyone else....
 
my parents say my car sounds fine just the way it is, so pretty much,
i need some good excuses to get this catback.
so far, my best excuses ive come up with are:
1) its my car and my money
2) this will help my education (in auto mecanics)
 
thanks, Adam