I would also keep it stock. When my Pantera was listed, the seller said it was all original because he thought it was. I felt bad because he got a ton of emails about everything that wasn't stock on it because he honestly didn't know.
It had under 50k miles but so much had been changed on it. I bought it because it was a super nice car and a solid foundation that I don't feel bad about modifying to make it better.
Your car is a different animal and you should be psyched to own it. Good luck with you Pantera, it sounds like an amazing car!