if you're thinking of going aftermarket engine management at any time... do it now!
it's a HUGE pita to remove the 1jz wiring once it's in there
other than that, should be great fun... commodoores with rb25s are relatively) common, but I've only seen one 1jz commodore.. definitly something to scare the v8 boys with
edit: incidentally my microtech came out of a 1jz commodoore (i think)