New best Quartermile time....with new exhaust

I had a custom exhaust done friday. It's simply 2.25" pipe directly from the cat-back. I decided to go with no resonator and had a Flowtech Warlock muffler added with a twin 2.25" tip. Previously, with stock exhaust, I ran 16.8 at 80.9mph and couldn't squeeze off any better time. Today, i ran the following:

R/T: .516
60': 2.509
330':6.907
1/8: 10.611
mph: 66.09
1000':13.817
1/4: 16.520
MPH: 82.92

I'm really happy

BTW, The muffler new is like 65bucks and the piping was $125.
It sounds really good too. Not too ricey and has a deep tone.