Ken have you tried Dan's other great innovation the MPG Remedy? Using my own recipie for it along w/ proper dose of Lucas upper cyl. fuel treat, and increased tire press. is how I got such radical
hiway test MPG's 2 weeks ago. I'm a real believer in those 2 mods along w/ the Groove of course.
The Subie needs substantially less throttle now- the rolling resistance has dropped way off, and the engine is more energetic and torqu-ier. So I drive with less throttle nearly all the time, so the butterfly is closer to the Groove. It's "in the Groove" more now. That should mean man. vac. is increased... Like all 3 elements are really working together. I can upshift oftentimes much earlier, the car and engine will just do it now.
I've adjusted driving technique to take advantage of course- "having the Power but using less of it".
We are Uber-Lucky to have Dan with us!
Tracy G