lol, the Fairlane, at 70 mph, with the windows up, is very, very loud. The weather stripping both around the windows and around the doors is 95% gone on all 4 doors, and in places, you can see the road through the bottom of the door sill because the weather stripping is no longer even in place. Plus I have a 4.7 liter V8 from the 60's, with 2 glasspacks on it, and exhaust exiting in front of the rear tire.
Oddly enough, at 70 mph and 2750 rpm, the exhaust is only just loud enough to overpower the wind noise. you can hold a conversation, but you must raise you voice to do so. Quiet talkers have to raise their voices considerably, the radio can be heard quite clearly when it is at 50-60% max volume.
With the windows down, everything is the same, just 25% louder all-round. Don't bother with a conversation, short of yelling at other passengers, it's not possible. The radio (aftermarket Alpine unit from 10 or so years ago) must be nearly maxed to even hear it.
Naturally, I cannot hear my tires at any speed.
The Blazer on the other hand, despite being as old as it is, and still having the original rubber in both doors and windows, is actually reasonably quiet inside at 70 mph. there is very little wind noise at all, and I consider the
wind noise to not only be the least with this truck, but it is comparable to my parents newer cars, such as the 98 Old Aurora.
With the windows up you can easily have a conversation with anyone else in the vehicle, although people in the back seat will need to speak up slightly to be heard. The OEM radio is clearly audible at about 20-30%. Tire roar however, is by far the most audible thing in the truck. For the last several years, I have had light Mudder style tires on this, and while they were shockingly quiet at first, as they wore down, they got exponentially louder. Right now the tires are very worn (in need of replacement actually) and the tire roar is quite loud, although still no-where near as loud as the Fairlane's exhaust.
The truck also happens to have a short 18 inch glasspack on it, near the back, but it also has a catalytic converter, so unless I am over 3500 rpm, it is still fairly quiet
inside (from all reports, its quite loud outside, but the sound does not travel at all)
With the windows down, the engine becomes the loudest thing. If the tailgate window is also down (which causes fumes in the rear seat, but not up front) the wind noise is only about 10-15% worse then windows up, and you hear more of the exhaust, but not much. Conversation is still easy if you are not on the Interstate. if on the interstate, the other vehicles on the road are usually so loud that conversation and radio is impossible.
The Saab is kind of in the middle between the Fairlane and Blazer, but it is closer to the blazer. There is much more wind noise in the Saab then the Blazer, but much less engine and tire note. With windows down, there is too much wind to have a conversation, but with them up, conversation is easy. The very old Michelin tires on the Saab are audible even with the windows up, but not loud.
Oddly enough, I can only hear the turbo in this at lower speeds, it's too quiet to hear over the other noises at any speed over 25 mph. I can hear the factory style bypass valve most of the time if I listen carefully though. The Saab does have a very nice exhaust note for a 4 banger though. Supposedly the muffler is a factory replacement that was put in less then 2 years ago.
TL; DR: The Fairlane is deafening, the Blazer quiet, and the Saab is louder then the blazer, but not much.