Keep the 68.
Any way you look at it, it is a much rarer car than the new one will ever be. Nothing negative about the newer CS's, they just don't do it for me.
You have a lot of investment $ and emotional involved to let Satan go.
The more bugs you fix, the less bugs there are to work out.
There are members on this site that had one when they were younger, sold it, and now have bought them again, wishing they never let the first one go. On top of having paid a much higher price than the one they had years ago. I have a few cars in my past that I wish I hadn't sold.
On top of all the that, I'm certain the gas, payments and upkeep of the 68 are less than just the payments on the 09.
If you have an option, if you can keep it,
Keep it
My humble opinion.