I've got some pics in the thread in my sig.
Leather CPR will not really get rid of the heavy oil buildup on the leather (the black spots). Leather CPR will do mild cleaning and will condition/restore (or greatly improve) the look and feel of the leather depending on the current condition of your leather.
To clean the black spots, use the "spa treatment" (google it for more info).
Basically you take a really hot moist cloth (almost steaming hot) and set it on the spot. Let the heat soak into the seat while holding mild pressure on it. After the warmth is leaving, gently
rub the area that was moistened. It will take quite a few applications to see a difference (but you can see it on the rag immediately).
edit: a couple of pics from the thread:
The pics don't do it justice. They feel so much better and look even better in real life. While mine are not quite back to the original "supple" feel of new (my back seats are), they are worlds better than when I started and are very comfortable now.