the drone reverberates in the cabin so the ute has small cabin so not as much time to bounce around (different frequency), where as sedan and wagon have larger space for the drone to bounce around and double up the waves for more drone, best fix for drone i have noticed is the rear muffler stick a stock one on will kill drone as its designed to do
The rear mufflers I have on now are pretty much almost stock, single pipe outlet merging into twin tips, a little louder than factory but it's still droning(not as bad as before as the overall volume has been greatly reduced by the rear mufflers), but particularly aweful at a sustained highway speed of 110kph. which suggests the issue is more with the front section (merge collector) as NAAF alluded to, and needs a muffler there.
Yesterday I met up 'Paradox' who kindly took the time to compare our systems, top class bloke all round. We have the identical vehicles with similar kms. 1" 3/4 extractors + 3inch system is identical to what I had before the modding, except for cats (mine 100cell, his 200cell), mine definitely stinks way more.
His wasn't as loud as my original set-up at start-up, idle, and under load/accelleration, and droned a bit less, possibly cat difference?
Anyhow, if the original shop can't fit a front muffler to my current set-up(surely they could) I'll take it elsewhere.