Actually funnily enough, noise would be a huge non-factor for them. My dad's hearing is terrible now even when he's willing to wear his hearing aids, and my mom is generally oblivious.
Thanks all for the great ideas.
Loving the idea of my dad hitting apexes. Fond memories of teaching my dad how to drive stick in my first car, a rusty Mk1 MR2 (a great idea), just weeks after I'd gotten the thing and taught
myself to drive stick reading Revscene forum posts.
And bcrdukes had to sit me down at a Starbucks to explain wtf it was that I just bought. "Nono you bought the wrong one. The '86 is like the worst one, there's no supercharger on yours."