har troligtvis fått reda på varför det bråkar… här e nog svaret…

Do I need an EGT bung?

No. The EGT bung is there for one purpose. It houses the EGT probe that monitors the
exhaust temperature so the engine heat does not break down the catalytic converter element if the EGT becomes
too hot. Since your new uppipe has no cat, you don’t need an EGT probe.

My uppipe has an EGT bung, should I plug it or reinstall the stock EGT sensor?

There is a chance down the road that EGT probe could burn up and pieces of it could be ingested by the turbo.
Plugging it is the best option. You will need a M12x1.25 bolt. They can be tricky to find and many go to
auto parts stores and ask for this type of oil drain bolt. True hardware stores are also a good place to find
these. You may consider a jam nut if the bolt is too long, or you could trim it down to fit better.
High temp thread locking compound is also an option.

What is the CEL fix?

2.2 KOhm 1/2 watt resistor. These are available at Radio Shack and are usually in stock.
$1 buys you 6 of them. You place it in the EGT connector, which is the bottom connector just forward of your
passenger side strut tower. It only has two holes, so jam one end of the resistor into each. If you do not use
this resistor, you will probably end up with the CEL code P0546 =Exhaust Gas Temperature Sensor Circuit Malfunction
(High Input). ***NOTE***There are two CEL fixes for the WRX, the other one is the rear CEL code P0420 Catalyst
System Efficiency Below Threshold, this code being caused by the lack of a catalytic converter in the downpipe.
This is usually fixed with an electrical fix or mechanical fix. This notice, though not important to this thread,
acknowledges there are two ”CEL fixes” and defines them individually to avoid possible confusion.