Everyone throwing around all of these "never's" need to cool it. KA's have problems because they're old, every 240sx had one at one point, and not everyone is a Nissan certified tech.

I still don't get the problem with KA timing. You time the cams once. That's it. If you're doing a million cam swaps, ziptie the sprockets to the chain so you don't have to deal with it.

As far as wiring, the KA is not different than any other motor. Done.

Yeah, a 2JZ is going to be a pretty low maintenance setup. Strap on whatever turbo, tune it with whatever you've got and rock out. You'll probably never need to open the motor unless you have a mechanical failure.

Cons: It's heavy. Really heavy. Like, the difference in weight between an Altezza (4-cyl, 6speed) and IS300 (2JZ and 6-speed) is something like 350 pounds, all other things equal. ...and the Altezza's 4-cyl has an iron block. Exhaust comes out the other side of the motor, which is only different and not bad. Packaging in a straight 6 is always an issue. And unless you do a turbo upgrade, some one in a 50-trim KA is going to blow past you. Oh the irony, if that happens.

If you have the cash, go for it. It can't be that hard.