IMHO, I love my nismo system. I still think it could be a bit louder/more aggressive though, which is why I'll be considering either berk hfc's or motordyne xyz with race cats and straight pipes.
Sorry to those that have k1, but, imho it just doesn't sound that nice to me and I'm not a fan of the looks either.
If you really wanted to be different, I'd love to hear another example of this, would probably be the only one in the uk also:
If you wanted plain, obscenely loud and imho doesn't look nice:
Here's my nismo though: