First off you want to be able to adjust your camber as when you lower your car your camber changes hugely!

If you have coilovers, the majority of front coilovers have adjustable top mounts where you can adjust your camber (on the front wheels) to a certain amount..

For the rear, standard arms in most cases dont give you enough adjustment so you'll most likely need to buy rear camber arms first, these for example, for your S13

http://www.driftworks.com/shop/p362/...duct_info.html


As you can adjust your front toe on any standard car you dont need any upgrades there apart from the likes of "Tein tie and track-rod ends" which are a stronger, thicker version of your standard arms and wont bend/breaks as easily!

For the rear, again standard arms dont always offer enough adjustment and as you adjust your camber your toe will automatically change too, so you'll most likely need adjustable toe rods such as these..

http://www.driftworks.com/shop/p359/...duct_info.html

Back to the front again, for drifting its quite essential to be able to adjust your castor, and standard arms in most cases arnt adjustable so you'll need adjustable tension rods.. Adjusting these moves the position of your wishbone forward or back and by doing this either speeds up or slow's down how quickly your steering returns after your turn (thats as simple as i can describe it!!)
When transitioning its handy to have your steering "self-centre"..

Adjustable tension rods...http://www.driftworks.com/shop/p360/...duct_info.html


Thats the basics, theres a few more such as adjustable lower arms which widen your track-width and allow for more lock which are quite handy, and traction control arms.. You can read more in this kit here:

http://www.driftworks.com/shop/p366/...duct_info.html

Hope that kelps!