Is it a burny oil/rubber smell? How many kms the car done?

Slight burny smell could be the rocker covers dripping some oil onto the exhaust/other parts which then results in burny oil smell... you could be due for a rocker cover gasket change soon.
If you look on each side of the engine and the bottom tray you should see oily residue. Its not a big worry but get it checked by a subaru specialist who can tell you if they need changing asap or if you can wait a few months. If they're leaking too much means you're losing engine oil and that's not good, so get the gaskets changed.

__________________
06 STi: 337hp @23psi on E85...
06 STi: 309hp @22psi on 98ron...