Heat wont really build up unless the car is parked and ur revving like crazy. I think..
liked the sound at first (like 3 mins of having it)
Then I hated it. It's too shallow, It doesn't give the deep rumble known in Subaru WRX's.
THe video was recorded with a Galaxy S3 - known to rob videos of bass. It sounded deeper in person but not deep enough.
I did this mod simply because I wanted to hear/feel my engine a bit more.
https://www.youtube.com/watch?v=_ydHDjMkHY0