Dava,

I doubt that the Empeg would fit in the ashtray spot due impingement by ECU below and heater controls above. If you do use DIN slot, then you have choice of 1) Empeg alone or 2) Empeg with another single-DIN head unit. Either way you must cut that ($85) silver bezel for the Empeg sled. If option 1, Crutchfield or installer.com can sell you a simple black plastic single-DIN pocket to fill the void (it may say Toyota or Nissan).

Per Tony's note, you may have found other more detailed WRX posts here. Also, take a look under forums on i-club.com. If you search for Rio Car / Empeg, you should find some pics of a professionally-done Empeg install (with a Nakamichi head unit). I'll eventually redo my install like this (Empeg on top).

Remember: Coffee and Dremels don't mix!

Jim