I'd just use 5w20, 5w30 would probably shear to a 20weight anyways, 5w20 is more stable.
TropArtic 5w20 syn blend is very similar to the motorcraft, and is usually cheaper, I recommend that, or havoline. With oci's of 3-4k for city short trip driving and 5k for mostly highway driving. For full syn, take your pick of 0/5w20 and keep the oci's the same until the warranty runs out.
The 2.3L is a mazda, it is most likely the same motor that is in the mazda3, and the base mazda6, with a few upgrades and different pcm for work use. Good motor.
[ August 27, 2005, 01:22 AM: Message edited by: Schism ]