This is a good thread.  Comfort, NVH, and entertainment are huge components in having a satisfying driving experience.  That was a real lesson learned from 
II Much.  
I started off with that car having no radio, heat, ac, much interior, or sound deadening.  Over the 3 years I drove it, I was continually adding things: 
1. sound deadening 
2. high end carpeting (Mercedes level)  
3. heat/defrost/AC (Vintage Air Gen IV setup)... I had to tear the car apart for that.
4. stereo -- a simple iPhone-based system, but I had tunes along with a sub-woofer
5. swapped the Locker differential for a TrueTrac
6. swapped the heim joints for Spohn's Del-Sphere Pivot Joints
7. had 3 clutches in the car before I found one I liked.
And I always regretted filling in the header panel and losing the windshield wipers.  And thank goodness Frank stopped me from using a Lexan windshield.  
 
jp