Where are you getting it tuned?
If it's at Hyperdrive, keep in mind Andrew's dyno is pretty pessimistic.
James' (Ten Four) 32 GTR made 370 hp on Hyperdrive's, then 400 on x-speed's.
Similar to me, my x-trail made 225 at Hyperdrive, then 259 at X-speed!
Your not making much power cos that turbo isn't really in its efficiency range at 16psi on a 2.5L.
What does your turbo's intake look like? try to fish some cold air from somewhere, then he should be able to add more timing!
How many kms does the 25 have on it?
[edit] cam timing should be ok, if you're making 300hp, then it's obviously not out that much!