I finally got the y pipe, sounds and feels amazing!! However during the installation the y pipe was too long to bolt to my test pipe. So they cut the middle of the test pipe and made it smaller by welding on a shorter pipe.. So now everything fits.

I'm not sure if that's the problem (shorter test pipe) but whenever i full throttle, I can feel the something rattling under my feet. The guy told me that I needed to change my motor mounts but I honestly didn't know what to make of it.

(The car does have 210k miles and I'm not sure if the previous owner ever changed the mounts)

What do you guys think?

 

What brand of TP was it? And yeah I’d say MM’s would help. At least there isn’t any clunking.

 

Check the heat shield that fits above the exhaust pipes. I used to hear a rattle after I put my 3" set up on my car, and when I finally inspected it, all it was was a single bolt that wasn't holding a corner of the shield up, so it was scratching and rattling when I drove.

Perhaps that could be the issue? If so, extremely easy fix.

 

+1 Check the heat sheilds.

 

It was the eBay brand that I originally had, they then cut the middle out and replaced it with a pipe of some sort.
I hope it is the heat shield

 

Probably the heat sheild but another possibility could be a bead from the welds they did rattling in the exhaust pipe. I had that same problem you describe and the exhaust shop cut my cat off tipped it over and a small bead came out. He just welded it back on and the noise went away. When you check the heat sheild try banging on the exhaust with your hand to see if you hear anything inside the pipe.

 

on the heat shield. When my cat converter heat shield starting rattling, I was convinced the sound was coming from somewhere inside my dash. Thankfully my mechaninc was able to figure it out.