Saab are still working on variable compression engines.
Holy grail i reckon
What we need is solenoid operated valves for fully mappable "cams" and then mappable CR to go with it.
10:1 off boost 6:1 at 3 bar, 40mpg, and happily ever after
Oh and all installed on a 3 litred scaled down version of the LS1 with DOD!