Tidgy

yeah, could be its pick up knock at high revs, tbh sounds like it my be worth a run on a dyno to see whats going on.

The heat in the cabin comes from the heater matrix which is heated by the engine coolant. So its basically adding additional cooling, which gets rid of the extra heat thats overwhelming the cooling system when its just the normal rad. When the headgasket goes it can cause gas to seep into the coolant from the cylinder, that gas is hot, which is what causes the heat to rise. so basically failed headgasket, add temp to the coolant system, cabin heater takes that extra heat out of the system. hopefully that makes sense. you can try a sniff test that looks for exhaust gases in the coolant, although its not always 100% reliable.

bit late, but tbh i would just replace them with a set of decent coils, correct setup wont be back breaking etc I've got tein flex z on mine and i love em, firmer than stock, but not back breaking etc

Could try importcarparts

Prices are all over the place, but i would guess 4-5k

have to say im not that up on subaru diesels, but i do remember crank issues being mentioned. tbh just keep up on top of maintenance and just drive it and not worry about it unless you need to.

try importcarparts

could try importcarparts, or might be a good time for an upgrade

I would get a specialist to check out the full system, thermostat etc, but with the heater affecting it doesn't sound great for the HG

I would get it to a specialist to get it checked out, could well be duff cam sensor, which could be bad if left.

Welcome :D get some pics up :D

Welcome :D

what colour is it? almost looks purple in the pic

I expect you need to use a proper delete kit as its prob stuck open.

importcarparts maybe a good place to contact

personal message/direct message

I mention buddget as it will define whats the best route to go, 22b's can be had for 250-300k, S204 hawk about 40k, a fully rebuilt/resprayed/refreshed classic sti around 30-40k, or a top qulity 22b replica for 60k upwards depending on spec. Thats the thing with it, budget will really define what you go for, by all means drop me a PM if you want to have a natter, i've been around them a long time, although i wouldnt say im a guru haha

Welcome, tbh it will really depend on budget. I doubt you'll find a decent classic sti without rot for under 20k now adays, do you have a budget in mind?

IIRC the plastic front is clipped into the housing, so once cluster removed can just unclip the clear front

I found the best way was just to convert the wife to them, picked up her forester after a rebuild today hahaha

the pipe is for the blowoff valve and yes you'll need it, looks like its for a a turbosmart style one, normaly they have an adaptor that gets bolted on, but this looks like it has a perminent fixed one. this is the adaptor, https://jdmaccessories.com.au/product/23650/ts-0205-2051-turbosmart-bov-adapter-kit-wrx-1999-00

No probs, sorry to be the bearer if bad news

the bad news is if its got rust then its not gonna be worth much and the cost of repairing it will never be covered by the sale value. You could try a specialist breaker company.

haha, yeah i bet

the sigma thing is for the alarm, https://www.jdm-manuals.com/sigma-m30-alarm-subaru-uk-forester-impreza/