Originally Posted by 1SICKM
Finding out the injector size is difficult. Do you think ESS or these tuners want to release their secrets and hard earned R/D. Gains from stock exhaust to catless are approx 20-25 whp. Gains from 535 to 575 pulley only are minimal. I saw approx 15whp. You would get more from upgrading to the 575 kit because the car is then tuned for it and the injectors are different. IMO - if your upgrading from 535....just go to the 600 or 625.
It's not difficult at all and certainly not a secret. I believe they're Bosch 40lbs but may be wrong. A shop would be able to flow test them to calculate they're size though.