The Good News:
I took everyone's suggestion and reran the compression test after Seafoaming. (Different gauge so the absolute values are different).
1 178 psi
2 181 psi
3 179 psi
4 180 psi
5 183 psi
6 177 psi
Done with 5 cranks using starter motor, fuel/ign disabled, all plugs out, warm, dry, and throttle all the way open.
The Bad News:
I was removing the injectors yesterday and started a small engine fire. Pooled gas on the supercharger ignited. I put it out within 20 sec and nothing, except the fuel rail seems scorched. I checked all the electrical connectors and hoses. No melting. No damage.
However, I used a half-second shot of an ABC (yellow powder) dry chemical extinguisher. The powder (mono-ammonium phosphate) is mildly corrosive if exposed to moisture (converts to phosphoric acid), specifically to aluminum. Before pulling the injectors, I blew all the powder from around the the injector port in the head 3x using cans of compressed air. I then cleaned the injectors with compressed air and mild electronics cleaner and swabbed the head ports thoroughly with a degreaser, before reinstalling the injectors. I cleaned the injector electrical connectors with MAF cleaner twice and water once. After reconnecting everything I hosed off the engine and transmission housing and took it for a spin (during which it behaved normally). The ABC leaves a residue when heated past 350 F and while I was very careful not to allow any in, I am certain some invariably found it way. I am hoping it was washed down with the gas and trapped in the oil, which I will be changing today now that I drove it 10 miles to circulate.
QUESTION: Am I OK?