Seat modification for headroom

[Wocka]

Hello,

Been to see a Jaguar XK8 today but found that it didn't have enough headroom which is a bit disappointing. This is frequently a problem for me as I'm 6'4" and fairly long in the torso. Leaning the seat back isn't an option as I'll get back pain.

Does anyone have any experience of having the foam in a car seat changed to increase headroom?
Does this make long journeys literally an arse ache?
What does it cost?
And any recommendations for who to talk to?

Thanks muchly

[smele]

Popular modification on Miata's (MX5's in the US) was to cut the base cushion in half. Reduced a good couple of inches of the head room. Can't say I noticed the seat being any more uncomfortable. Could be an option on the Jag.