Rich,
Evo's run MINUS ignition values in certain circumstances (but different bore / stroke to a Cossie, so not directly comparable) and Simon actually used to run SINGLE figures on his (but melted several engines ) with an MD240 turbo.

Ask Euan what ignition HE runs on the top line and then look at how reliable his engine is at 2.5 bar, compared to say - Aides high comp one.... .