stage 1,2 protune? Whats your AFR? If your using an off the shelf map, cobb tunes those pretty rich, so you might have some false knock with something rattling around. If you have a pro tune you might just be running too much timing for this heat. you can try decreasing the timing by up to three degrees via the live tuning feature on there Ap. I only use qt, chevron, or shell, haven't had issues with any of them.