Cabin Noise Level

[WhipE350]

I'm guessing you mean with the top closed. I know my 2000 'S' had a fair amount of wind whistling noise because of the side view mirrors and the slop of the windshield at least compare to my 987 and 981 (which was very quiet). The cooler the temps the whistling was louder. Sometimes whistling can be caused by poor adjustment in the hood where it latches.

It sounds like you are hearing a lot of road noise, if it is constant on smooth roads then it is the tires (what brand and model tires do you have) or bearings. Bearings will often get louder when turning too. What is the mileage on the tires, some get nasty noisy with high mileage.

Is the road noise on bumpy roads and if you have never replace any suspension parts have them checked.