Hi Michael Reese,
I just actually bought a Z and am currently drifting it now. I would say this is all my opinion so far and I've attended 2 events so far and it will drift no problem. So in my opinion the following things to do in order to get your car in "drift ready shape". DKmura is right though, if you plan on drifting this car, i would have another car to drive as a daily...
1. Welded rear differential - this will be the cheapest and easiest way to get you sliding. Depending on where you live you should be able to find a local auto shop to do it. i would suggest looking on facebook for car groups in your area to reccomend someone! At this point you can technically drift the car, but the things beyond this make the experience a whole lot better depending on your budget.
2. Enjukuracing.com has a great harness bar so you can get at least a 4 point harness to keep you put in the seat (big help). Go to enjukuracing.com and find grafitti harness bar. I also reccomend Bridge moto 4 point harness. It's easy to install and comes with all the hardware to attach to your stock seat.
3. I feel like a decent HYDRO E brake is a must too. You can clutch kick and still get it sideways or feint drift into a corner, but this will be a big help. Again, depends on your budget. Enjukuracing.com has a lot of good stuff for decent prices. ASD Makes a great hydro brake and if you need more explanation let me know. You will also have to disconnect the ABS fuse under the hood when you get it installed.
I feel like these things are the absolute necessities. I'll list some other items in order, and this will all depend on your budget. Of course, if you can afford good new cheap tires this is the better option, as they don't wear out as fast as used tires. you can drift all day on 2 sets of tires unlike with used tires you might go through 3 or 4 sets.
4. A good quality clutch - Competition clutch is what I put in mine. Several hundred bucks but you can thrash on them.
5. Racing bucket seat with bracket ( i bought the Corbeau seat for like 300 ish bucks and it's decent without breaking the bank, i also bought the corbeau bracket and it sits too high for me. My helmet hits the roof and i'm only 5' 6". I've heard the Buddy Club seat brackets fit lower)
6. Removable steering wheel quick disconnect with short hub from NRG along with an aftermarket steering wheel (NRG has some good stuff without breaking the bank)
7. Coilovers- A good set of true coilovers unlike the seperate shock and spring you have setup in the rear now. BC makes a good set of true coilovers probably around $1000.
8. Aftermarket radiator to keep your temps down.
9. Intake system -
10. New exhaust and cut out the catalytic converters to free up some power.
11. Past this there's a ton of upgrades you can do, but i would say run this setup for a while and learn the car. The Z will certainly drift no problem. Learn the car and improve your skill and then you can start getting fancy with angle kits, etc.
Hope this helps!!!