Well I went the cheapest route.
Took it to Frank - I dropped it off Friday and had it back Saturday (wow!)
He repalced 3 piston sets (rod/ring/piston) and my belt tensioner.
The landings on 1 piston was actually missing chunks of piston
The other 2 had badly cracked landings.
Cylinder walls, tops of pistons and everything else looked fine however.
All said and done $1500 drive away.
Compression is better again, and no more smoke or blow-by.
I have a CEL now however - "31 Detonation sensor"
Checked the knock sensor plug and it looks fine and secure.
Logging shows I either have 0 knock or 9 knock - no other number.
Any ideas what else I should look at? oir just replace it? (Car has 160k on it)