Tech is right, removing them without remapping will cause a VERY lean condition under WOT. Going by exhaust color to check fuel mixture? That being the case I'm running super lean, couldn't possibly be the U4.2 causing my exhaust to be white. I've had my bike on a dyno 4-5 times since last winter, checked A/F every time and it's perfect. Exhaust is NOT an accurate way to check it. Do a plug chop, or use an A/F probe/wideband setup.
I also have a hard time believing you have one of the fastest ZX-10R's in the south.
Dont try and educate me about gas u4 is cheap i run mr12 and mrx01
I do rb20 and rb25 wiring into s13 and s14's 300.00 shipped 24hr turn around turn ket start guaranteed! PM me for more details!