I think I'm now convinced that my car pulls harder when I have a vacuum leak...

Just how rich IS the WOT map that it would have more torque when it's running leaner?

I'm guessing you could actually make noticeable increases with just an Super AFC or piggyback?

 

Yes, people have proved that you can gain noticable HP just with a piggyback and a good dyno tune. Something like 10 or so hp could be possible.

 

I could believe that. I can definitely feel the difference in first gear between running leaner and running rich (especially with a properly heat-shielded and ducted intake).

...although I think I need to work on my suspension first...