I would suggest that you post the same question at the UK Cobra Club Website,
www.cobraclub.com or at another UK site for car enthusiasts
www.pistonheads.com which has a dedicated Le Mans forum.
There's well over 60,000 UK car enthusiasts who go over to Le Mans every year so you won't feel lonely or be the only one speaking English, and there will be many Cobra's going over too. Get in quickly and you may blag a lift over there in something interesting.
For the more Cobra orientated Le Mans enthusiast, its generally thought that the Le Mans Classic held every two years (next meeting will be in 2008), is the more refined and enjoyable. Watching proper classic racers from pre war up to the 70's , being driven as intended, far smaller crowds, lots better atmosphere, and a chance to see the classic Cobra/ Ferrari/ Daytona/ Corvette wars relived in the French sunshine surrounded by fellow Cobra enthusiasts within easy staggering distance of a cold beer and a hot BBQ.
The toilets though are to be avoided. By the third day they are like the battlefield of the Somme, though with a worse stench, more disease and more death !!
Cheers,
Tony