Buying Nissan Silvia

[Kessian]

This is my first time on the forums, so just trying to get a hang of it.
I'm in the market for a Nissan Silvia, and only willing to spend a max of about $10k on the base car itself, so i'm wondering where's a good place to look? (Live in Perth, Australia btw)

Also, i will be spending about $500 a week on it to modify it a bit, so i'm wondering what is the better Exhaust Systems (including Extractors), POD Filter to get done at the start (Looking for quality, not cheapness).

Later on, when i can actually get insurance, How much will a single turbo kit cost?

Lastly, what year would be better for a Nissan Silvia?

Your help will be very much appreciated.