k24z2 - 08 honda accord 2.4l i4 - cai ( ebay ) with ram extension (autozone) to front of bumper. No cel. cheap af. sounds good. A few different videos of sound on my youtube page.

This video shows cai extension:
https://www.youtube.com/watch?v=BJa5C6lz8Gg

rand-eye,
Go to your local autozone, oreilys and buy the o2 sensor tool (~$9.00). And see if they sell some 02 sensors as well. Ask Autozone to see which one of your o2 sensor is faulty.
Then proceed to watch a DIY youtube video.
Erok

I replaced my muffler with a borla xr1 sport (12 inch). I have a RV6 downpipe pre cat delete. I did not buy a high flow cat or a test pipe along with the dp. At the moment this setup is burning my secondary cat making it smell like rotten eggs when I punch it hard. This still sounds amazing in my op...

I had this rattle while acceleration problem happen to my 08 Honda accord 2.4l,i4.
I went too balance the tires and rotate at discount tire where i had bought my wheel.
Its free. It seems to have worked for me.