It's either the rings are gone or your valve guide seals need replaced. Time for a compression test AND leakdown.

After you do a dry compression test pour a tablespoon of oil into the cylinder(s) that were low or off from the others and do the compression test again. If the compression is higher now you have worn rings. If the compression stays the same it's time for a leakdown. Listen for the following while doing the leakdown.

Air from the oil cap is worn rings or toasty pistions
Air from the exhaust/downpipe is a leaking exhaust valve
Air from the intake manifold is a leaking intake valve
Air from the radiator is compression leaking into water jacket
Air from adjacent cylinders is blown head gasket in between cylinders or a cracked head or a cracked cyl wall

 

I just think that if you are this worried before boost, theres nothing like the peace of mind knowing all your parts are good. Life with boost will easily have you twice as worried.