An intercooler hose leak would not cause the car to not even be able to rev up at all, or take forever to get to 25 mph. I've had some pretty massive vacuum leaks, and was still able to drive the car, just didn't run well.
The reason I suggested the cat was one time, years ago, my high school business teacher had a turbo supra. He had it for a short time, then noticed it began to run rough. One day it started to slow down, and he had to give it more gas to keep going. he ended up having it floored, and still only going a few mph. He pulled over and called a tow truck from a pay phone. He noticed from a distance his catalytic convertor was glowing cherry red. The car caught on fire right there and burned. I would think that if anything else was that bad on your car, we would get some codes, or something you've done already would have helped.
Check that coil and module, and lose the cat anyway, let us know. good luck!
