Last night i installed my DC stainless header and the install went fairly smooth. I started it up and sounded fine on idle. I then took it out for a drive and heard this terrible rattle occuring at almost all rpms. I tightened all the bolts up this morning and still heard a rattle in the cockpit, but barely anything when sitting outside the car. I put the top down and the noise went away.

Do I have to drive with my top down forever? or is there something simple I am missing.