Anyone had their std cerb exhaust sleeved?

[hugepiece]

I was wondering has anyone had this done to their standard exhaust? I know that often Chim and Griff owners have it done. I'm not totally sure of the look of most of the sports systems, they always seem to not fit the cutouts properly. The SP system seems to be the exception but thats lots of money! Is this worth considering doing this? or should I bite the bullet and buy a JP or similar?