I just installed my Megan exhaust yesterday. Sounds great to me... particularly for the price. The welds look good and I don't see how anyone could call this a mediocre product. I was actually really impressed by the quality. The only thing I wasn't impressed with was the fact that it didn't come with 4 required nuts to mate with the factory bolts. A trip to the hardware store and $1.97 fixed that though. I did find it to be a bit irritating that the nuts were't included. Maybe the same happens with the Agency Power? Not sure...
Does it drone? Sure, a little bit, but all others will too unless you spend a ridiculous amount of money.
I'll enjoy the $1000+ I saved on some track events. In my opinion my money is better spent there.
So far this seems to be a well engineered product. It's certainly not a piece of crap like people assume it is just because it's cheaper. You don't always get what you pay for. I don't feel the need to pay for someone else's R&D. If you think I am crazy then you are the person who probably buys Advil vs generic ibuprofen. If it makes you feel better to spend more for a name then go for it. I don't think it's wrong to do... it's just not for me.