Yeah 300 no worries as long as your tune is good. I once saw a B16A do 200kw for 6 years on OEM internals, but admittedly that's a shorter stroke. You should be fine all the same but I wouldn't chase any more power than that.

The yanks tend to go 400-450HP ATW in their B18's but that's on a US dyno, however you'd probably be fine at 350HP.