Do I need a new mechanic?

From numbers I've seen on the Air Gap, they seem to beat pretty much everything out there across the RPM range. I'm not sure what to think about the spacer. Open hole designs usually bump up the HP a bit at the top end at the expense of TQ at the bottom end. Don't know what the 4-hole space would do. With the relatively small torquey cam, I would probably skip the spacer.