Exhaust system, strange things?

I had a new cat-back system installed on my Accord. I had one of the two resonators removed. Now for the question, My car is loud as hell from 1k-3k rpm's after 3k rpms the exhaust goes quite??? I have dual exhaust with Magnaflow straight through mufflers. I also had the piping increased from 2" to 2.5". Is this normal??? I just wanted to make sure that the system is working correctly. It just seems really odd that the exhuast noise would go from "chest vibrating loud" to almost non existant after 3k rpm's. Also, when I get out of the car I can really smell the exhaust and muffler, which I couldn't with the factory system???

Thanks in advance for any info you guys have on this.

Your engine is loud at lower rpms because your not burning your fuel as much as you do at high rpm during the power stroke. This is becuase your engine is more efficient at higher rpm and it is also most likely running leaner. Your engine is also under a heavier load at lower rpm. As for the smell, the stock system is more closed off and restrictive, this means that your exhaust charge will spend more time in the cat so your unburnt exhaust will be burned in the cat and cant leave an odor.