I am not expert or anything close but talked to a guy about my car.
He said that you really don't want high compression with turbos.
He said the ideal compression is about 9 to 1 for turbo's
He said you have to make adjustments for cylinder pressures.
To much pressure and you'll mess up the bearings or blow head gasgets
or the heads. I'm sure there is other factors that come in to play as well,
maybe the rings. Kurt