Jezza
This is what we have done, and were running challenge so some of the costs maybe higher if you go competition.
Most of the answers are in the sup regs.
TSW entry is about $2k.
On top of that you have accommodation in Pemberton, meals (excluding Saturday night as thats included for driver and navigator.)
First time out, you also need to do a reece of the roads to write your own pace notes, so from Perth this could be another night in Pemberton. ie drive down drive course and write initial notes, next day revisit and drive home.
There are a couple of courses run each year for rally navigation, LCCC and Rally Action do them, possibly others. Worth doing for driver and co-driver.
Crew. TSW only has one (well it did last year) designated service. This is after the first up and back of the first hill climb, on the Saturday morning. As this is designed to be an introduction to Targa events, if you have issues, these can be addressed outside the the SS if needed. So a mate helping out can be all you need. All going well someone to have your lunch ready Saturday, ensure you have enough drinks on board (Needed on Sunday as its pretty much 6 stages in a row), but they are groups (GTi Girls who do offer this service for a price)
Car prep. Do a few of the Rallysprints the same organisation does. Gives you a good idea of what you need including safety items, eg 2 extinguishers (2kg total, first aid kit triangles and kitty litter requirements are the same). Typically, new brakes (pads and discs, bleed lines), new oil and clean filters. Not so sure requirements for radiator
Tyres, I'm only in challenge, and it can rain in Pemby this time of year. So with 130kph limit I bought RE002 on a Bridgestone 3 for 4 offer $600, and are using them again this year.
New cost this year is the Rallysafe fitting kit. $175 plus GST and postage, but can be used for other events that need Rallysafe, eg TW and possibly the dirt rallies depending on the level of the event.
Extras, helmet intercoms, eg stillo, Proper helmet rather than the 1698 standard and have to retro fit comms back in with HANS posts. However this can be done, and have done it on my wifes helmet as they are different brands, and the 2 intercoms won't easily work with each other. Race suit, looks better than king gee overalls, (fairly sure you now need a one piece covering, but these are in the CAMS manual), camel back for drinks. balaclava helps protect the inside of the helmet and helps with keeping on the sunnies when you pull the helmet on.
Race boots, gloves for driver. fairly sure these are mandatory, again see CAMS manual.
This year were adding race seats and the 6th points to the harness. Have a harness bar and 4 point harness last year, but not required for Challenge. I also used a HANS device, and working on getting one for my wife this year, not mandatory for our class, but the trees are very big.
For competition, most of the above is mandatory, plus the roll cage.
Then there is after event maintenance, breakages...
Tim