There can be as much as a 400 degree plus difference between readings in the manifold to readings post turbo. Manifold is the best place, there's a good (read: easy to get to) location in the drivers side manifold just before it mates to the up pipe. The manifolds are easy to drill and tap, just pack the tap with grease so you don't get chips in the manifold, they will damage the turbo. Make sure to run the probe wiring away from the rest of the exhaust.
Last edited by overl0rd : 05-24-2006 at 08:08 PM.