Indeed, I know its not the most accurate spot, but purity and all that. I'm not too concerned about absolute precision (otherwise Subaru would instruct differently ie cylinder 3 gallery plug), more just gauging that I'm in line with other systems considering all this stuff is almost 30 years old   I still wonder how in the heck it could ever read 120-130+ in that location though...

ooh it's a haze of those days when I cared about that stuff hah, yeah 90 sounds about right?   A tapped Drain plug is also the coolest spot? (heat rises) and ya getting max airflow / cooling in the area too if you've not got a undertray too

OP isn't a regular here anymore and I'm not ECU savy : but the 1st question is But why?   is your car Auto?

I love updates like these hah : proof people read (or search) the forum & why I try & help keep it alive  

The year is 2026 and I've had a WRX NA Bug eye for 15 years (that's 2x cam belt kits if you're counting) and the trim-extras list goes like this: HID headlights flared guards  Wrx seats  raised suspension  boot spoiler  Rev counter centred in the instrument cluster Momo steering wheel with powershift tiptronic  fog lights  side skirts  Wrx brakes Twin piston slide calipers on the front    BTW I still get 7.8 ltrs/100km out of it and it's not fast but nimble enough.