I have noticed what I think is drone around 1800-2200 RPM (vibrates in car a little and minor buzzing sound inside the cab).
Yes, there is a very different sound, similar to a harmonic at quite excatly 2000 RPM. Not as wide as 1800-2200. I have noticed this on 4 quite different cars already (3 x V8 and one V6, all with Borla). I assume this is inherent to car initial design, and all were strong after I installed Borla. Even the SHOGUN V6 did that. The rumble is replaced with a different sound, at a very acurate frequency, and the result is not as enjoyable as the rest of the RPM range.
My 2012 GT
does it too, but I dont worry anymore.