It isn't that loud with both boxes removed, just sounds a bit blowy on tickover when the engine is cold. Mine has both boxes removed, bonnet lining removed and a Ktec induction kit. Loads of pops and bangs but it's still not as loud as the average Corsa with dustbin back box! It's not quiet either mind, but motorway cruising is barely and louder than normal, certainly no droning in the cabin as that would send me mental.
