If you actually want a drift car, it would be more economical for you to just buy a drift car and keep your LGT as your daily. As mentioned, you're going to go through engines and transmissions, in addition to body panels and whatever else gets messed up in the many crashes you endure while learning the car. I'm not trying to be a buzzkill on your idea - sliding a car is fun - but just consider that you'll be sinking a few grand into an LGT just to get it to slide, and when it does, it's not the best platform for it, so when it goes, it won't be with ballerina-like grace. Whereas you use the same amount of money and get a beater 240, E30, Miata, etc, and you'd already be mostly there. And when it's in the shop (it'll be in the shop a lot unless you plan on getting good at doing bodywork in your driveway), you can drive your LGT.
Edit: And ignoring what car you're actually going to put it on, if you want a predictable breakaway of the rear end, you'll need a mechanical LSD. Apparently these new cars with the E-LSDs work well enough, but I don't imagine you're talking about $80K+ cars here. Below that, open, VLSDs, and even some Torsen diffs, are all unpredictable relative to a mechanical LSD. They are usually a large contributor to when a car gets a reputation of having snap oversteer.