It's a mid-engined car. Don't trailbrake. A MR or M4 car normally doesn't like to be braked in anything but a straight line.
Reason: You have the engine behind you. When you are on the brakes, the weight shifts forward, but this engine acts like a pendulum that will swing the car if you begin to turn while still turning. One thing that can help ameliorate this condition is touching the throttle a bit while braking.
While this is about the SV, the LP 640 in the toscana challenge behaves roughly the same way. Very loose under braking in a curve. Throttle braking helps and stabilizes the car. If you can handle a 4-wheel drift in a 4 wheel drive car (or more correctly: recovering one without a lot of speed loss), then don't blip the throttle. To help prevent it from drifting, blip the throttle a little or keep the throttle on a little while braking. This means that if you are using a wheel, Left-Foot-Braking is nearly required to keep the car stable.
Once more, either brake in a straight line, or trail brake whilst applying a tad of the throttle to stabilize this beast. It will perform very nicely