if you have 4wd, K is not going to happen.
another b20z would be a direct plug and play option.
anything else is going to require some work, mount changes, wiring changes, etc etc.
There'a always the option to build the replacement b20z as well. any LS (non vtec b18b) cams, etc will work in the head as they are pretty much the same head casting-wise.
or, the vtec head swap option... but that requires wiring, new computer, etc etc.
and still, as above, if its an auto, the auto probably won't take too much more power than it is currently being fed. honda auto's are known for being pretty weak.