Head Gasket Replacement Shop Recommendations- San Francisco Bay Area

[Edit] Well, crud, after just taking the time to type in all the blah, blah, blah additional diagnostic bits and pieces below that I have gathered... I read your post #18. I think I need to step away from the monitors and get the car to Gasket Masters for an assessment...]

Since my wife drives it, I really have no idea how long it took to loose a 1/2 gal. of coolant. I may have stated before the last oil change I did, but I think that I would have noticed lowered coolant in the reservoir. So it may have lost coolant over these last 5 months (≈5600 miles). But my wife first reported the engine shake one week ago 1/28. At that time I added the half gal. of coolant. Since the few 6-mile round trips the car has been used for, the coolant level has not dropped from the full mark at all. Not sure what that info means.

As the engine cools overnight, especially with our current overnight temps between 40ºF to 48º-ish, doesn't the coolant contract as the engine temp matches ambient temp, then essentially be close to atmospheric pressure by morning normally? Two nights ago, I was doing MY first drives in the car to test 'when' and for how long the shaking happened. When the Autel Live scanning showed 195º, thinking that was abnormal (glad to know it is not), I pulled over to look at the coolant level. It was exactly at the Full mark that I had filled it to the week prior. I decided to open the reservoir cap, and a big woosh of pressure was released. No coolant/ liquid came out at all. But the coolant level in the reservoir, strictly from releasing the pressure by removing the cap, was then ≈ 1/2" 'above' the Full mark it had been just before removing the cap.
One data point from the Autel Live drive that I forgot to report was the 'Electric Water Pump Speed'. Autel says Target speed is 2450 rpm. When Coolant temp read 187ºF, 'Elect. W/P Speed was 3125 rpm. When Coolant temp read 195ºF, 'Elect. W/P Speed ranged between 3400-3500 rpm.
Back to last week, 1/28, when my wife experienced the knock/shudder, she told me she checked the web that indicated to her it was likely low coolant. That day, I added a half gallon of coolant. I did a scan and it showed P0117 'Engine Coolant Temp Circuit Input Low' (maybe coolant below sensor level) and P148F 'Engine Coolant Pump Over Revolution' (maybe impeller cavitating due to low coolant). After adding the coolant, I cleared those codes and they have not returned.

I plan to remove the wipers and cowling, pull the plugs and check the cylinders with a borescope, and report back. Am I correct in assuming it is fine to drive the car for either short test run(s) and the eventual 50 minute drive to Gasket Masters leaving the wipers and cowling off? That way, I can recheck Cyl. 1 status if needed, but also to save shop labor time for that piece of whatever repair I end up getting.

What does "may not choose to use a JDM based on a comment in one of their videos" mean?

 

rjparker, Thank you very much for posting these vidoeos, especially the Car Care Nut one.
After watching the first video, seeing the details he describes, I now clearly see your point that I should just take it to Gasket Masters, have them diagnose the issues and listen to their recommendations and options. At 19:30 in the Car Care Nut video, he lays out how to frame the decision to repair vs. cut your losses and buy a newer version of the car you love(d), so the whole car is newer, not just the engine.