You're right, in that the headers do look like you have just done 3 laps of Barbs, but if the headers were leaking, you would see :-

A loss of power (which you mentioned)
The car would sound pretty crappy if the leak was big enough, as in a gasket that has blown out, leaving a decent hole for gasses to escape. I remember my car sounding like a 2 stroke dirt bike when I got on the loud pedal.
Black soot around the area of the leak, which you should be able to see quite easily on the heads or the gearbox / master cylinder.
If there is a crack, this can be more difficult to find, especially with the wrap you have on the headers. The problem will get worse though, as the headers heat & cool, the crack will obviously get worse.

Remember though that the exhaust system is under pressure, I can't imagine air being sucked into the headers in any way & you would need raw fuel to be going in also to create the heat.

I would suggest ripping that wrapping off also (the wrap will also be part of the heat retention in the headers, helping them to stay red hot), as its only a matter of time before it falls off. Have a look fr abnormal back soot areas that you can easily wipe off with your fingers & if that doesn't come to any conclusion, drive it until the loss of power gets worse & then the issue will be easier to find.

Hose them down when they are that hot. You'll find a crack or two then!

[QUOTE=Master D;782142]Hose them down when they are that hot. You'll find a crack or two then![/QUOTE]

^^^Ever helpful!

[QUOTE=Master D;782142]Hose them down when they are that hot. You'll find a crack or two then![/QUOTE]

Put down the crack pipe Dave :p

[QUOTE=GTB Liberty;782200]Put down the crack pipe Dave :p[/QUOTE]

It is the silly season Andrew anything can happen.

[QUOTE=munya;782205]It is the silly season Andrew anything can happen.[/QUOTE]

Scary hosing down headers with a water ...

Yeh ... nah ain't goin' to happen. :D

My EGT are around 350 cels off boost/cruise. Well below glowing red temp. I'd suggest there's more of a problem than an exhaust leak.

Would that be more of a blockage than a leak? Like a collapsed cat or something? - That would also cause a loss of power, and sound like a leak too?

Quick google cherry red is 760 c or so.

[QUOTE=scary;782154]^^^Ever helpful![/QUOTE]

Always happy to help!
😆