I don't really get any drone with my intake and Gibson exhaust, but the Gibson is known for being one of the quieter exhaust options. It does seem to have a certain resonance around 3000 rpm under load, but I don't really mind it. What took me awhile to adjust to was the intake hiss, but it's all good now.

Glad the upgrades worked out for you - I also found that the combo made a lot bigger difference than either probably would alone (certainly the exhaust alone didn't do much but sound) - synergy is good.