I've done a couple of long hwy drives in my '64 Mini. At first I thought it didn't have any sound deadening, but it turns out to have some. The engine is a 997 with twin SU's. It seems to have pretty short gearing (I'm in 4th gear by 40 mph), but it will still keep up with traffic without a problem. But the engine is screaming. After long drives my ears ring so I keep ear plugs with me. Keeping speeds at 45-50 is much more pleasant.
My car was purchased via Hemmings from a seller in SoCal and I had Heritage do the pre-inspection. I mused about driving it home to Philadelphia but they advised against it. Part of me wishes I had done the drive, but I can understand not recommending it. Regardless, I so wish I could do the 2016 Great Race from NorCal to Chicago, despite the noise.