Your'e not crazy, I found the ZZII to handle like a damn pig too....
I found that it needed ALOT of tuning with LSD, Diff, and Suspension.
MR / 4WD / Lightweight = Understeer Central
This is because there is hardly any weight over the front wheels due to the MR configuration. Being a 4WD, the front wheels are also being used to drive the car, and therefore it is extremely important to have weight over them, so they can have enough grip to actually do their job (i.e. make the car handle well).
Acceleration further intensifies this problem too, as even more weight is taken off the front wheels as it gets transferred to the rear.
Because the car is extremely light, the weight of the engine itself makes up a huge percentage of the total weight. No matter what car, or how much it weights in total, if the engine itself makes up a large percentage of that total weight, the handling of the car is going to be greatly affected, differing in type of effect depending on the position of the engine.
This shows how the fairly rare configuration of MR / 4WD / Lightweight is very tricky to engineer, tune, and drive. As frustrating as it is though, when you get it right, the results are pretty amazing.