I guess maybe I'm more skeptical of the fact that any company would be willing to put that kind of R&D...into an XJ :laugh:
Our motor's aren't known for performance by a long shot, and aren't remotely THAT great of a market share anymore.
LOL, true. That being said, the majority of XJs I see on the road these days are modified in some way.
I put the cooler in front of the mechanical fan so that it's always working, even when the vehicle is moving slow or is stationary. My aux fan very rarely kicks on, so most of the time the aux cooler would be doing next to nothing at very low to zero speeds if it were in front of it.
That's also the hot side, so the hot air coming off of your cooler has less impact on the radiator's efficiency there since temperature deltas are still relatively high (probably 20-30* above ambient, so 140* air tops hitting the 210*-ish radiator).