check compression of your engine - if it's good and engine doesn't take oil - than leave it. I don't think you will loose a lot of hp with high mileage, all depends on an engine condition.

 

Consider using AutoRX. It's an incredible metal cleaner you add to your crank and run through the application.

When you complete your treatment in a couple months, your compression will DEFINATELY rise significantly, your seals will be re-conditioned and your insides will as clean as that 20K engine you're talking about.

While it can't fix damaged parts, it is the BEST engine restorer I've ever come across. I was skeptical when I bought it. But when I opened my valve cover to take a look, I was flawed. Didn't have a camera then, but I will personally pay you twice the cost if you don't feel a difference.

THIS IS NOT SNAKE OIL and IS the next best thing to serious engine work.

My brother was so impressed, he's running it on his SC2.