I had the same problem (I'm 6'3"), and have a great solution that is pretty inexpensive. I had Bascom Trim & Upholstery (in Santa Clara, but they have other locations throughout the Bay Area) trim about 1/4" of the foam off the lower portion of the headrest. They removed the leather from the top portion of the seat, had me sit in the seat to determine where the foam was hitting my neck/back, and trimmed it down. It took them less than 2 hours. I was prepared to do the same for the passenger seat, but you don't notice the difference between the front seat headrests unless you know what to look for, so I opted not to spend the extra money for that. Bascom was recommended by the Fremont SC to me (Tesla contracts with them for upholstery), and Ryan Bascom oversaw everything. I was totally impressed with their work.