Yeah, I've been using a B&M supercooler (#70268) for about a year now. Install wasn't a big deal. One day I was poking around under the BMW and decided since the 3/4 inch think B&M looks like it'll fit nicely behind the fan with no cutting, etc., why not? I can always revert back to OEM (I cut and sealed the lines to the OEM cooler in a manner that let's me get a mulligan), but right now I like having trans pan temps down in the 150s in summer driving. I wish I'd have checked the temps before - my all kinds of not scientific: "wow - that's hot" pre-check is not sufficient to draw a conclusion on. Anyway, this was more of a "I think I'll do that on Saturday, and see whaddup" exercise rather than a solution to a problem. I ran it all year (well, I still do) including near zero winter temps, and have not had any inclination to change it back. Really, the only info applicable to most folks is trivia "hey, what trans cooler fits easy between the fan and radiatior?"
