That's true, how difficult ya think it would be for  "novice"?

You have to start somewhere. What do you want to do?

Well it is due a service just so I was thinking of breaking it down a bit as I've not much spare time at the moment probably start with the most urgent engine oil?

Hardest part of changing the oil is jacking car up lol. If I was you I would buy a good trolly jack and Haynes manual and go from there. I cannot answer your question as I have now idea of your skills. 

Ok fair comment not really done that much on cars bar wheel bearings few alternators starter motors the odd oil.change. all on basic 90s cars. I'm a plumber by trade so not bad with hands on stuff, just dont want to balls it up can it not be a work zone trolley Jack lol

You will be fine. Trolly jack and axle stands unless you like living dangerously.

Again personally i would spend a lot more after all it will be supporting a car while YOUR are underneath it. It will work sure. I would advise axel stands too. I would spend the whole £145 on jack and stands maybe more but that is me.

Yeah true true prob spend a bit more be oright when it's on the stands. Just been lookin through receipts had a bit done to it recently

USA workshop manual all I seem to find is that right?

try this

 

https://www.ebay.co.uk/itm/Subaru-Impreza-WRX-STI-2004-2014-Haynes-Workshop-Manual-89080-NEW/202820981553?hash=item2f39129331:g:UAEAAOSwv7ldyvlp

 

I only said get Haynes manual as I thought you were new to this. If your a plumber by trade then I expect you to be able to change the oil anyway. Haynes manual is useful though. Looks like your ok for most of it looking at the invoices. Do not get the invoice with just an oil filter on it, did they change the oil as well? The oil costs are not on the invoice. It also looks like the previous owner threw some money at it which is a good sign.

Jay has the right manual.

Cheers Jay found the right manual last  night 15.90 ebay👍. Oils ordered 5w40 shell helix ultra, plan on doing more myself now too siluro so book will come in mate. Odd but maybe already had oil or somert. The one that says gear oil is that for the Front an rear diff?

Gear oil is the gearbox. You can find a dipstick under the intercooler near the turbo. Rear diff is separate.

So when somebody says front diff do they mean gearbox? 

Checked it when seen the car nice clean fluid in their, changing the rear diff fluid looks a peace mate eh

34 minutes ago, Daryl said:

So when somebody says front diff do they mean gearbox? 

Yes. Rear diff is just two plugs. Easy.

 

Rear diff is easy - I use a nitrile syringe and small piece of tube to replace the oil