ok...

1. super charged hood. the stock '02/'03 wont fit unless you change the headlights and bumper... talking major cash.

2. there is a Supercharger you can add to 2000 / 2001 xterras Heres all the info ... runs about $2k

3. LAX pointed out the calmini kit. Infact there are several body lifts for the xterra... Calmini is just one of several... 4x4/4x2 is irrelevant... and 2000/2001 should be interchangable
here are two more:
performance accessories
A /C