Cabin noise

i commute a lot in the ep3 and the noise is driving me nuts.
last weekend ive changed the 3 inch midpipe for stock, now the whole exhaust is stock but its still freaking loud in the cabin?? at 130kmh its droning and the drone is gone just below 120kmh. how is this even possible?

the only mod the car has now is aem v2 shortram is this causing the drone?

http://i68.tinypic.com/2v0040o.jpg

Try installing sound deadener. It might solve your problem.