Changed my oil in my 08 wrx (35,000ks). Used motul 300v 5w30 power racing, $60 for 2 litres (lucky my car only uses 4, unlike the gtr which used close to 6 with alll the external lines and coolers, cans etc). Very happy with the results. The car seems to rev easier, sound quiter and accelerate smoother. Who would have thought such a difference could have come from using a better oil. To be fair though, the Subaru service centre were using a 5w30 semi castrol, so one would expect such a difference.