Engine Performance problem
1999 Saab 9-5 4 cyl Front Wheel Drive Automatic 135000 miles

I have been replacing hoses on my SAAB to repair a vacume leak/ loss of power/ compression problem I have been having.

I took my car on a test drive yesterday then without warning smoke started to billow out the tailpipe w a loss of power then died. No sound.

I coasted back to my garage then restarted the car without any problems accept that it is still smoking and has water dropplets out the tailpipe. (white smoke)

I checked the oil=no water or milky residue
I checked the coolant level=tiny bit lower but still in range
I checked the coolant resivour for gas "bubbles" coming up=none

My Question is....how do I know for sure whether my heads blew or it is my turbo without have a compression testing guage? Is there anything else I can check or look for?