The negatives I know of this motor are that they have a propensity to bend exhaust valves in competition use, they bent so many of them in the old GT Production series that Toyota ended up listing stainless exhaust valves as a "stock item" to get around the rules. I personally have broken a 2ZZ, oil surge at 8,000rpm going around a bend after a toyota service 1500kms before, the oil level was low and it ended up spinning #1 & 4 big ends. Result, brand new short motor from Toyota required. The engines are unable to be overbored (unless you change the liners) as there is nil room between the cylinders, and they use metal matrix bores. I have many photos of one disassembled if anyone is interested.
From a performance aspect, I have driven a ZZT231 celica as a daily driver for around 3 years now, the engine is phenomenal compared to a 4AG, when the 292deg "big" cam kicks in they haul, and you can putt it around like a corolla at normal speeds without it being annoying. Can't say the same for the gearbox though, almost all C-series FWD gearboxes are junk, they wear synchros out at a ridiculous rate. In an AE86 they would be a great engine, as they are lighter than the 4AG, physically smaller and have stable low down torque and a big end kick. Obviously there are a number of challenges to face physically mounting the engine in an 86, such as no RWD gearbox existing, etc. but with enough cash it would be a very successful transplant.
