You can bring whatever you want. With Keigwin if you bring an aftermarket you get ONE shot with it, too loud? You're done. ( This is because once almost everyone brought an aftermarket pipe and Keigwins had over ONE HUNDRED sound violations in one day, and track management told them they were inches from losing the right to use the track. So now there's no slack.)
I got meat balled 3 times with a stock exhaust on my old gsxr 1000. Friken ridiculous! Love the but hate that sound rule. I show up on myrace bike and baby it around turn 5-6 till the end of the day now. Then i blast by the sound and blow by the meatball right before i go home! LOL.....
Neil's got the program down! Just short shift through 5 - and don't drift out leaving turn 5, the sound meter is on the right. Keep to the left of the track so you don't buzz the meter and you can rip again after Turn 6.
Surprise. They now have mobile metering and move the station sometimes.:rofl