I think there is some serious technology going on with Mazda and their new engine line.
Green Car Congress: Mazda introducing 1.3L direct injection gasoline engine as first SKYACTIV-G unit
This is almost 2 years old. I know the Diesel seems to have low compression, but there are other things that must be considered like two stage supercharging, Direct sequential injection, and independent control of the exhaust camshaft, which allow the lower compression and avoids the issues with emissions aftertreatment.
Green Car Congress: Mazda introducing 1.3L direct injection gasoline engine as first SKYACTIV-G unit
I don't think this engine is cheap if they are using it in a racing version. I think Mazda saw the separation with Ford coming and knew they needed something truly trnasformational in order to survive in the World market.
I read that the gasoline version uses 5 injection sequences for every combustion stroke, so it's 14 to 1 compression ration is incapable of preignition as it is simply not possible with only a small precentage of the fuel injected intitially, and the peak pressure point is delayed and prolonged which improves efficiency.
Not sure how it will all work out but it is certainly interesting to watch. I was a fan of the rotaries until the fuel consumpltion issues became insurmountable, but at least Mazda is willing to take the risks involved with advancing combustion technology.
regards
Mech