[PeteKz]

Seats are the biggie. Some years ago, I was a planning to substitute sport seats for my OE comfort seats in my 1973, but then decided to keep it looking like it was, and rebuilt those. They are so much more satisfying for 99% of the driving I do.

After that, noise reduction. Lots you can do here, but I think the most important is eliminating all the wind noises you can find, because they all add up to a fairly uncomfortable amount of mid- to high-frequency cabin noise. Highest on this list is closing the gaps around the door and window frames. Obviously make sure the door seals are in good shape and making contact ll the way around. In particular, make are there are no gaps at the front of the door where the window frame joins the door. Later models have a small plastic fairing intros gap to smooth it out and let the seal make even contact. If your car doesn't have those, buy them or fabricate something. If you took out the sound-deadening padding in the back and bottom of the car, put that back or install Dynamat or something similar.

HINT: You can use painter's tape or something like that to temporarily seal various gaps and see/hear how much difference those make. You can also lay out and tape in place a bunch of heavy blankets in the back of the car to see if that reduces engine noise before pulling everything apart to install sound deadening.

The seal around the hood prevents air and noise coming into the frunk and then into the cabin, so make sure that seals all around. Bonus: It will keep the crap you store up front dry, and help your heat or AC keep the cabin temps comfortable. Make sure all the grommets in the front panel and inner fenders are tight.

Basically, it's about paying attention to a bunch of little things that add up, not one or two big things.