Finally got around to modifying my nissan injectors. These came from a 97 I30. I think the red tops are 270cc. Took about 10 min per injector, its really not that hard if you use a dremel with a grinding wheel. I ground off most of the cap at the end, then used a flat screwdriver to pry the edge up. After peeling off the outer edge with a pair of pliers you will see how much more you need to grind. Pretty simple. Just be careful near the center as you dont want to touch the pintle.

Modified injector on left, stock on right. The stockers just have a restrictor plate to control the injector flow rate. 270cc to 550cc in 10 min