[Broke_as_****]

Pulling the turbo with the engine in: Not having done it I can't tell you for sure, but having looked at some engine bay pictures and some shots of engines on the ground, I would say yes. It might be a pain in the ass but it should definately be possible. Usually if you can get to it you can remove it and getting the the turbo doesn't look like it is too much of an issue on the Pulsar.

As for everything else, I would just start checking the basic functions of the motor, starting with the simple stuff and working up. Spark plug gap, timing, boost leaks, ecu codes, sensor shorts...etc etc. It's usually the long way around a problem but it will usually net the best results in the end. You might find one main problem or a few smaller ones but even if it's a blown turbo at least you'll be confident that the rest of the motor is in good working order.