The speaker size is 6 1/2"
I bought Speakers from Sonic Electrinix and if you type in the vehicle model information if gives you the correct size. The speakers did fit.
The 2001 Volkswagen Jetta has an inline 4 engine.
The 2001 Volkswagen Jetta has a 2.0 L base engine size.
The 2010 Volkswagen Jetta has a 2.5 L base engine size.
The 2003 Volkswagen Jetta has a 2.0 L base engine size.
The 2004 Volkswagen Jetta has a 2.0 L base engine size.
The 2008 Volkswagen Jetta has a 2.5 L base engine size.
The 2002 Volkswagen Jetta has a 2.0 L base engine size.
The 2007 Volkswagen Jetta has a 2.5 L base engine size.
The 2012 Volkswagen Jetta has a 2.0 L base engine size.
The 2011 Volkswagen Jetta has a 2.0 L base engine size.
The 2006 Volkswagen Jetta has a 2.5 L base engine size.
The 2014 Volkswagen Jetta has a 2.0 L base engine size.