my mates a series mini is running 2 bar on a stage 5 hybrid t2 type turbo on pump fuel with cr of 8.2:1, he is still using the carb, but has megajolt ignition
its all down to the build, qaulity of parts and the tune,
at the end of the day its all down to what the engine builder decides he is happy with, and if your doing the build yourself its down to what you feel comfortable with.
people with starlets are always far to scared to try new things, different things there is to much scare mongering, i will agree 2 bar is pushiong it at that cr, but there is no need to say it cant be done.
if i were to build another engine i would be going for a cr of 8.2:1 and running one of the new borg warner efr turbo's @2bar, with decent management.
anyhoo as stated its all down to the engine builder, and its best to do your own calculations