I believe those benefits are usually only for engines that have VCT and even further variable lift also. As the Focus does not have that (the SVT has the VCT on only one cam). I think you also tend to have more knock sensors and other electronics to determine detonation and then the best timing and fuel map combo to use.
Please correct me if I am wrong.
also 1 MPG increase, for at minimums 10 cents per gallon for a 1MPG increase? looks like around me its about 15 cents average more for 87 (our 91 octane up here at 4,700 feet). $1.95 more for 13 miles distance... that's not cost effective, as over two fill ups, i would go 26 more miles for $3.90... at this moment I can get 1 gallon of regular for less than $3.90 and go further than 26 miles on it.
2001 ZX3 2.0L Zetec-
Hatch Nation #42
Going through Rebuild See "The TICK Build Thread" for details (http://www.focusfanatics.com/forum/showthread.php?t=289168&referrerid=62897)