Just a quick note on this, because I've seen it a million times before...
A shop gets backed up and the owner decides to pull it for whatever reason before the car gets to be fixed. Maybe it was on the backburner because they were extremely busy or whatever the case was... that's not really why I posted...
The reason I posted is to say, who says the problem is fixed?
I've seen many cases where I see something I don't like in a tune file, where the car will still dyno fine but could over time develop an issue, etc. Some places don't take the time to fix it or know the difference so "there are no problems". They're not datalogging, they don't catch it, there's a million things that could happen.
There's a good chance that maybe JDM was seeing some weird returnless voltage stuff that has an affect on transient fueling, etc. They could have seen battery voltage trying to compensate for a draw to keep pressure from dropping at WOT? Maybe it was an alternator or battery issue, ground, wiring, whatever. I don't know the specific issue. Someone else (RPM in Delaware) comes along and makes a pass on the car without datalogging fuel pump voltage at the table and voltage at the pumps but gets a somewhat stable air/fuel plot and calls it a day. What the hell the voltages are adaptive, right? They don't know anyway, all they see is decent pressure and somewhat stable AFR's and the car makes power. Voila... tuned... WRONG.
That's the difference. If the problem was fixed, I'd recommend you have a shop look at it who specializes in S197s. I know RPM in Claymont, DE... I'd trust them with my LS-based Chevrolet all day long. Fran's a good kid. I wouldn't ever bring them an S197. Then again, there's probably less than 10 individuals I'd trust with an S197 for tuning.
Just sayin... maybe you should let JDM tune it. Let them take another stab at it. If they get jammed up I'd gladly help them. Sr/Jr/Ned are great dudes.