1) It is recommend to provide signal to signal distance about 3-5 time the width of the signal trace
2) It is recommended that all lines on the GPIF II bus could be length matched within 500 mils.
3) The 500 mil requirements ensures that the delay between the signals lie within 1% of the total period considering the typical propagation delays for stripline and microstrip traces in PCBs (150 to 200 ps/inch). We also recommend using 22-Ω series termination resistors to avoid reflection on these lines.
Please refer our hardware design guidelines available in AN70707: http://www.cypress.com/documentation/application-notes/an70707-ez-usb-fx3-fx3s-hardware-design-guidelines-and-schematic
We also recommend you to cross-check with the hardware files of Cypress DVKs: http://www.cypress.com/documentation/development-kitsboards/cyusb3kit-003-ez-usb-fx3-superspeed-explorer-kit