Just about to change the oil and filter on my 2003 STI been told that 5-30 oil may be to thin, the handbook says to use 5-30 anyone got any suggestions ? Also fully or semi ?

 

I use Silkolene/Fuchs Pro-S 5w-40, as recommended by the the Oilman (Opie Oils), They are doing a 25 % off for Easter

I would give them a call, and they will spec an oil that suits your need bests ie mods, daily driver, track day etc etc

Mine is a daily driver 15-20k a year, with mods/PPP to around 340/340ish, i also change oil every 5k as its a) A good habit to be in, and b) i think the oils performance drops off after 7-8k anyway