I will post some pics......Little busy now, just give me some time.
You are also right, 7AFE or 5AFE is a good option. But 5AFE was already present in car, and it was neither in good condition nor bad, you can say it was in normal or above normal condition.
We first consider these options: 5AFE, 7AFE, 1NZFE, 2NZFE, 1ZZFE.
2NZFE was dropped because we think it might be under power but later we come to know that we were wrong.
We also want some fuel average as the car is a daily runner so we dropped 7AFE & 1ZZFE.
We only left with 5AFE & 1NZFE. 5AFE was already in the car and serving well. If we again put a 5AFE then first thing is that we almost get same fuel average and the second thing it is difficult to find a 5AFE in good condition as compared to Z-generation.
So we decided that why not go for 1NZFE and get more fuel average & power than the previous generation.