The BMW z4 replaced the BMW z3 in late 2002. The BMW z3 was introduced in 1996 shortly after staring in a James Bond movie. Not as easy on the eyes as the z3 but just as nice.
BMW Z3, E85 Z4, X3, X5 and X6 are assembled in Spartanburg, South Carolina.
The 3 series, except for the Z3 had cabin filters. The Z3 had no cabin filters. Beginning in 2003 with the introduction of the Z4, BMW began installing cabin air filters.
A very basic Z4 would be about $47,000 for a 2011 Z4. Like many other cars you can buy different "editions" of a car. In the BMW Z4 there is a Z4 sDrive30i ($47,000+), Z4 sDrive35i ($53,000+),Z4 sDrive35is ($62,000+). The same goes with the Ferrari. I can't give you the exact differences but it would be $100,000+
The 2013 BMW Z4 has 16 valves.
The 2006 BMW Z4 has 24 valves.
The 2007 BMW Z4 has 24 valves.
The 2012 BMW Z4 has 16 valves.
The 2008 BMW Z4 has 24 valves.
The 2011 BMW Z4 has 24 valves.
The 2010 BMW Z4 has 24 valves.
The 2014 BMW Z4 has 16 valves.