The only way to diagnose it properly is to get on the dyno.
Simple.
Im sure the tuner knows more about this sort of stuff than you do.
If you think its coils, get some coils off another car that you know are working and test. Check for any boost leaks ect
Other than that you cant do much until you get it on the dyno.
And of course its running lean, you have just put a bigger turbo on that flows a hell of a lot more air than stock the ECU cant feed enough fuel to it.
The ECU is most likely hitting R&R.
Clueless people indeed.