I have the LTH with the 12" resonators. Love the sound from this set-up. Get it over 5,000 rpm, and it's pure music.
On down shifting. I get some lean back fire pops out of it. Reminds me of the track. I picked up about 14hp with everything. But I'm in need of a tune though.
Here's my Nismo on a mustang dyno last week.
Click on the picture for the video.