6 1/2 inch for the front doors and 6x9 for the rear deck. You HAVE to remove the back decklid in order for the speakers to come out. They are dropped in from the top. You can also go to Crutchfield.com to get the specs for your car and the wiring codes.
The 2003 Hyundai Elantra has an inline 4 engine.
The 2003 Hyundai Elantra has a 2.0 L base engine size.
6.5 for the front and 6 for the back.
P195/60R15 or P185/65R15
The 2001 Hyundai Elantra's came with the 2.0L engine
The 2001 Hyundai Elantra has a 2.0 L base engine size.
The 2011 Hyundai Elantra has a 1.8 L base engine size.
The 2007 Hyundai Elantra has a 2.0 L base engine size.
The 2012 Hyundai Elantra has a 1.8 L base engine size.
The 2013 Hyundai Elantra has a 1.8 L base engine size.
The 2014 Hyundai Elantra has a 1.8 L base engine size.
The 2002 Hyundai Elantra has a 2.0 L base engine size.