it's a .12 pipe on a OS 12TR(P)T engine, sorry for not including the info earlier.
about the decibel: I measured it by using an dB meter (commonly used in audio contests), I'm not sure about the accuracy of the apparatus, but it's used for local dB contests over here. I's measured at 90 deg (angle) at 5 meters at full throttle,... I don't know about how loud it actually is,... but I can't apply WOT when I'm near the car or while tuning, though...
thanks for the link to ROAR, I'll check what it says
