Apparently a shop in Washington state does them. I read this from them on the only (really) Z900RS forum, in the U.K. looks like the cost is near $300. Does a flash really do all this?
“The fuel mapping is on the conservative side with our mapping. We have also lowered the fan engagement temp 10 degrees Fahrenheit to keep the coolant temps down.
Here is this complete list of modifications off our site:
Custom IAP Fuel Maps
Custom TPS Fuel Maps
Custom Ignition Timing Maps
Custom Ignition Dwell Maps
Adjust RPM Limiters
Adjust Fan Temperature
Disable Stock O2 Sensor
Disable Fuel Cut
Disable PAIR Valve