just having a little think about it,,,,, when i think of the chaser's the 1jz came from i think that the gearbox will be a huge problem fitting into the existing tunnel for the car! also gear stick placement will be a problem! have you seen how small the original g/box in these E30's are???? they are tiny so it may be an issue......
although the E30's use linkages external to the box so this may allow a bit more room for a larger box, that only being id the 1jz g/box is internal linkage like the rb25 boxes!