Your stock coil has always been a good one, and if you had asked this question a couple years ago, I would have advised you to keep your money, but your coil is 10 years old now, and is going to start to show it's age before long. That being said, I'd replace it. I doubt you will notice a hp gain, but you might notice more pull at higher rpms. You
might. If nothing else, it will give you peace of mind. I'd recommend a Crane PS92. MSD coils are either noisy or fail prematurely, and Accel always makes me think of those God-awful Street Stock wires (although I do love their 300+ Race Wires). It's up to you. Those are just my opinions.
Take care,
~Chris