You don't need much if anything to "drift". Your stock ebrake is plenty if you're just getting into drifting. If it's garbage you should start by fixing it. Go to a few events and get a feel for you car. Practice really does make perfect. If you're thinking about getting into serious drifting, coilovers, a hydraulic handbrake, custom front control arms, a bumpsteer kit, some camber, subframes, and racings seats with harnesses are a great start.
Vortecd4v can point you in the right direction.
Heyyy, this names familiar you follow me on Instagram haha.
I agree with all of this minus the stock Ebrake. Mustang stock e brakes barely hold the car let alone lock them up for drifting. I've seen people try to make them work and they snap cables before working usably.
As
Poxenham said, the FMC group is probably THE BEST source of Mustang drift info currently available as its just a decently big group of people building mainly Mustang's. His e brake is rad and I really want his watts link setup, they are AWESOME for drifting because of how much grip they get.
You really don't need anything to start, enough power and an LSD are stock, the only thing you'll worry about is the clutches wearing out. One more quick thing is to see if your car has rack limiters on the inner tie rods, take them out and you get a tiny bit more angle so that helps. I've driven my car COMPLETELY BONE STOCK and it did alright, then I stripped it with a set of springs and drove it like that for about a year and it was great until the clutches in the LSD wore out. Welded is awesome, and cheap/free.
If you want to do more then that, actual drift suspension (read mad angle yo) it's money, and I wouldn't really recommend it unless you plan on not keeping it as a daily because you'll have to increase the front track width, cut shit, most people make only solid bushing stuff as well so it wears relatively quick for street use + uncomfortable. Not saying you can't but I wouldnt recommend it.
To give you an idea on setups, here's my car with a shitty ghetto exhaust + springs, bone stock otherwise.
[video=youtube;DeVkdVrRHG4]https://www.youtube.com/watch?v=DeVkdVrRHG4[/video]
Here it is with Coilovers, modded knuckles, custom control arms, welded diff, ect ect..... this was also slammed as shit with bald front tires and had horrible geometry but it still did good haha
[video=youtube;lUbff6ZXU4E]https://www.youtube.com/watch?v=lUbff6ZXU4E&t=131[/video]
OH, and you're in Oregon. Head up to evergreen sometime and I'll show you all you want or give you some rides!