When I had a T16 I fitted a K&N into the airbox.
On the T16 the inlet is on the exhaust side so the standard box allows you to suck in cooler air, but check the hose isn't perished over the manifold. Mine failed.
I had an ITG on my 4/4. It added a lot of induction noise.
On my T16 I fitted a Librands exhaust but also a Librands manifold.
The manifold really frees up the engine, especially mid range torque.
