i don't think you can upgrade the 4in1, but what you can do is take it out, take it apart and drill cooling holes in the case.

i've upgrade to the unbreakable skids, great upgrade.
other things i have done:

micro heli alloy swashplate, my stock one separated.
micro heli inner shaft, mine stock one bent in a nasty crash
alloy bearing holder
eflite alloy lower rotor head