Welcome fella DIB owner! Sounds like I have some competition in the most miles in a year contest. Lol. I've had mine just over 4 months and 9200 miles.
I too have GT500 axle backs. For the price and the fact it's an OE Ford designed parts, they have a great sound that is hard to past up, not to mention a little bigger tip to fill up that rear cutout. There is no drone, at all, which I think is a must for a DD. I also liked the Borla S-Type exhaust when I was shopping, but to make the exhaust note worthwhile, expect to drop $1k on the entire cat-back system.