I asked Ken Morgan of www.eurocars.bz about this, his response follows:

 yes, the compression ratio is a big part of the
power boost....  And No, there is no need to worry about a knock sensor or
detonation because the shape and proportions of the parts in the combustion
chamber are set up to cancel a condition known as surface detonation....
Engines that do not have surface detonation typically do not detonate at
all, and no spark knock......  These engines hava been electronically
tested, with sensors attached, for surface detonation at 18 kilohertz and
none was found.....