I got a 96 gsr and i put the apexi n1 exhuast cat back on about 2 months ago. All the sudden it started rattling a little bit when i reach 4,000rpm. I am going to tighten all the bolts today from the header back. If anyone has had the same rattling noise help me out.

 

Its crap, as soon as I bolted on my Spoon N1, it stared rattleing, I read somewhere that the noise comes from the heat shields, but I dont know if I take them off, the heat will damage the car, anyone?

 

The heatshields on our cars rust then rattle like hell. Here's a thread regarding safety of the heatshields.
https://honda-tech.com/zerothread?id=775180