Okay i've tried a couple exhaust and i've db tested each of them,
1)5sizen border iii - 75db idle
2)Bee - R - 78 DB IDLE
3)Blitz Nur spec-R 80db idle
4)Kakimoto full mega N1 single 87db idle
The kakimoto full mega N1 single is freaking loud, its about 78-80db with the silencer on but once its off, the sound its freaking amazing. It has a very mellow gurgle but sounds nice around 3k rpm, but absolutely amazing floored. None of the youtube video you can find on youtube can describe it, you just have to hear it yourself. The setup is with catalic removed with straight pipe, mid pipe+resonator and back exhaust original full set from kakimoto. If i was to rate the sound, it would be
1)Bee-R exhaust (extremely rare to source but sounds absolutely like a GTR35 howling, amazing amazing sound. You can find a white german skyline with the bee-r on, i'll try to get the link once a get home from office.Its a complete different sound, makes your rb sounds like a VR38dett engine with TUBI exhaust on it)
2)really nice low bassy sound around 3k rpm, amazing when boosted.
3)blitz nur spec -r, overated. Lots of video on youtube, once u try kakimoto n1/bee-r u won't look at blitz nur.
4)5zigen border iii - its a damn quiet s-flow exhaust. Never got a problem with the cops. I would rate this slightly nicer and better than the nismo ne-1.