My Girl's mustang is leaking coolant. I noticed that area of the thermostat housing was leaking. i further looked into it and noticed that the intake manifold was cracked where it meets the thermostat housing. The entire manifold is plastic. When i searched for a intake manifold replacement I found some but in the thermostat housing area it is no longer plastic, is it an upgrade? Then i notice it says * does not work with pcv heated models* What does that mean? http://www.partsgeek.com/catalog/2000/ford/mustang/air_intake/intake_manifold.html would that be fine for her vehicle?