i have a d16y7.. i changed the exhaust mani to the d16y8s.. i havent installd a catalytic converter since the exhaust shopped installd it for me.. its also connectd to my own 2.25" pipings i had done to my muffler.. ever since i had the y8 exhaust mani installed it rattles a lot more.. its very annoying.. when i hit high rpms itll rattle for quite awhile until i turn off my car or something.. whats making it rattle more??

 

make sure your heat shield in your cat has all the bolts and stuff...

 

Mine does the same thing but it is an Ej1 with a 99 Si exhaust on it. I will check out all the bolts this weekend. Hopefully that will fix it.