I would not recommend it, the difference is not very huge, and you might fall into resolving issues than enjoying it. I had drums and dics now,here is the check list:
1.Install rear GT discs
2.Get (rare) Handbrake cable for disc
3.Replace Proportionate valve with 60/40 ratio(GT Valve)(rare)
Drum brakes at rear are not bad. Instead, install Big Front Double ventilated Disc from corolla98/AE101 which is a bolt on fit and improves braking a lot ,only rim has to be 14inch+
You can install master brake cylinder a.k.a servo from ae101 to get better brakes with ligher touch