I found out that passenger's side bracket will FIT if you use longer turbo to IC hose. If you are using a Samco y-hose from WRX, you can simply cut it and use 1 7/8" OD coupler from Advance auto part to extend the length (first posted at scoobymods.com).
Be sure to get either V7 or V8 USDM air splitter kit as stock WRX won't work effectively. According to Big Sky WRX, you will need V8 when both brackets are mounted correctly. You will need V7 when only driver's side bracket is sitting correctly.
UPDATE: On 02-03 WRX with JDM STi hood scoop, you must get a JDM V7 air splitter. USDM STi air splitter will not work.