Well here is my experience. On my 69 Charger w/440 I ran a 3" exhaust, Hooker Super Comp. headers and Flowmaster 40's.
HATED it after 1 day. Oh it was cool and all that, nice and loud people would stare and point and then lights would flash. Never understood that part. Couldn't come home late at night and not wake up the entire neighborhood, and that's at idle. Loud may be for some, but for me it isn't everything. At crusie speeds you couldn't even think and a long trip would consist of 30 mins because by then you would have had enough. Didn't really drive the car much becuase of that. Some people say the 3" pipes is what caused a lot of resonace in the interior and others agreed with that and said the mufflers didn't help.
So fast forward to my Challenger, put a 440 in it, hedman headers and a 2.5" exhaust. I'm running Magnoflow mufflers and
LOVE it! NIce rumble at idle, whn you hit the gas, people know you have something under the hood, once on the highway at cruising speed, it is a nice mellow tone, not to waery, drove the 6.5 hours to Carlisle w/o it being a problem. Not sure if it is the smaller pipe size and the mufflers, but it is pretty quiet in the interior, but has a nice sound when standing behind the car. Best bet would be a nice quiet exhaust and some electric operated cut-outs! Hmmm, who has that now?