SG9 Forester STI. Parts in common with Impreza/standard fozz

Starting to get a few issues with my '06 FSTI so trying to find a good source of parts.
Does anyone know the ins and outs of what this car has in common with both non sti foresters and also Imprezas of the same vintage?

In the near future I'm going to want
-Discs and pads
-Suspension parts (top mounts)
-Drive shafts
-Headlights (hopefully sorted but lots of LHD parts on the market to confuse things)

Are any decent number of parts available via UK dealships? There's only so many dodgy looking websites and ebay listings I can look at before going mad. Very little confidence in ever sourcing the right part.

If drivetrain bits are predominantly all Impreza STI then at least it would be easier to find aftermarket support for some stuff. Similarly, if a lot of parts are common to UK foresters then I might have a a decent amout of luck via a dealership.

Hello
Pads put some yellow stuff ones in no need for a warm up to work well , option 2 and cheaper are black diamond road response pads , the brembos on the Fsti are the same as an earlier sti Impreza 2001 to 2006 or so , your pcd is 100 the sti went to 114 pcd from around 2006 ish onwards , mtec brake discs is what I have on mine , very well priced , driveshafts that's unusual they go , sure it's not the centre diff , I have a lot of Fsti spares , the jap sites are partsouq , mega zip , Amayama , you also have Rock auto but always order via fed ex as that's the total landed cost , the headlights are specific to the model , you can polish or change the whole lens , a new unit is very expensive and best from Japan as cheaper , yours have hid fitted you can upgrade the builds use Phillips or ostam night breakers , don't get cheap bulbs waste of money , your subaru standard bulbs are about 150 each , the tilt motors fail they are not interchangeable so best adjust and left , the 07 had a auto tilt mechanism earlier models had the toggle , I hope that helps , pm me if you need to know more , im running 3 Fsti at the moment , I've scrapped two of them , don't change the turbo they do benefit from a map , if top mounts have gone which again is rare , is it coilover time , bc or Tein work well

Before you go buying drive shafts try cleaning all joints out and repacking with fresh grease, they are well made items and sometimes all they need is swift regreasing for another life.

My ballast part was via ebay , it appeared a number of types would work , and were around the 60 quid mark sometime ago , you will need to try and seal the light first , taking apart is not horrendous , if you don't try and seal it first depending on how long it took to fill you could end up where you started , as above you can buy a new lens and seal , the ballast resistors are perfectly placed to get wet , you could try drilling the bottom of the light in its lowest places , and on one ballast I sealed the wires in the light with silicon , and wrapped it to keep it dryer , some times lights come up for sale on ebay , or best option but expensive is buy new , my last set were from Russia a number of years ago