Tried everything to eliminate exhaust drone... any ideas?

About four years ago, I had a custom exhaust set up on my 01 Integra. This set up included 2.25 inch piping from the cat, a louvered resonator, and a greddy evo replica exahust. It was considered my "perfect" set-up since I increased my car's performance along with a deep rumble as I drive (plus I was on a college student's budget then). There was very little exhaust drone, and it was tolerable while driving on the highway. But starting about 6-7 months ago, the drone became increasingly louder that it was unbearable.

I tried changing the muffler first, and replaced it with a street series Magnaflow. I had experience with one before and it was quiet so I tried the Magnaflow idea again. The drone was still there, so I replaced the old resonator with a new hi-flow, straight through resonator. That didn't work as well.

Would I have to drop a size down in piping diameter? Should I go back to a louvered resonator? Any help would be great because this has been bugging me! :banghead: