Did you first calibrate the wideband by itself in open air then calibrate it within TS? What do you mean the wideband's instruction chart? Do you mean you set up a custom voltage range using the values from the widebands instructions?

Your arm x series does not need calibration out of the box. Adjust voltage values until the gauge matches TS. There are several threads on this

Extremely rich and lean
 

Needs more info. Methinks you should've spent more time getting the issues sorted out while N/A before "installing a turbo."

Let alone don't tell us anything about your setup since we're all mind readers here...

I mean, don't bother posting a datalog either.

Yeah you need to remove the turbo, do a LOT more reading, then get your car running naturally aspirated with bigger injectors and THEN think about installing the turbo.

edit: at least, you need to do that if you want any of the more knowledgeable people here to help you.

If fuel cut isn't turning on anymore, you probably have a vacuum leak in your Intake Manifold, causing it to never go low enough KPA to trigger fuel cut.
You definitely need to get your turbo off and sort your tune out.
It took me months and months and months to get an understanding enough where I can happily tune my car good enough, then I put on my turbo and was able to understand what was going on and what needed changing and shit I still have ages to go before I would be able to get the most out of the engine and truly tune every thing perfectly.

You need to give us way more information, photos of your setup, engine bay, changes you make, logs, logs when your doing pulls, put markers on the log (hit spacebar when logging) and tell us what you were doing in the car when that happened.
Then maybe someone will come help you more.
You have to take it into your own hands and read EVERYTHING.
DiyAutoTune has some great articles on tuning stuff, theres a wordpress site called roadsterzoku which also has some good info on setting up a miata with megasquirt.
read read read, take off your turbo, get your car working and running WELL on N/A then come back.
Don't touch things like Accel enrichment till your Fuel VE Tables are good, one badly configured fuel amount, plus another badly configured fuel amount makes for a very badly fueled car and you won't know which one is wrong.