You know, I?m not sure if ?Loud Quads? are a thing.. chap I bought my car from I believe bought them new, & he described them as such. They are definitely louder than standard and sound lovely, but not as aggressive to my ear as Xpowers. Would easily pass track day limits I would think, as in the past I?ve had no issue on various tracks running Xpowers. You can I think still buy new from Zero, so maybe give them a call.