AR Pani Exhaust
It makes good power up top after tuning, has a massive dip in the midrange that can't be corrected with tuning, is pretty friggen loud, looks to have excellent build quality but will eventually crack and need service. Speaking of service, customer service is horrible. Like pretty much the worst customer service you will ever experience.
With that said, I held it in my hands briefly but gave it back promptly due to knowing that it would crack sooner than later. I also heard it in on a Pani at the Indi GP and it is easily the most raw, visceral, MotoGP-esque exhaust I've heard.
THe concept is great.The longevity is poor. The customer service is poor.