Clearly he's made his decision - though I agree that in the complete absence of heat when attempting to initially start, it makes absolutely zero difference whether air is drawn from around the manifold or from around the grille; and though the Bosch manual I've studied also makes it clear that the sole purpose is to improve emissions during initial warm-up; and though it makes sense, in that really, really cold fuel won't vaporize well in really, really cold air, so emissions levels are reduced by warming that air slightly for a few minutes so the fuel vaporizes and combusts efficiently but even so when you crank the car over and it hiccups once, the manifold doesn't warm up any so this doesn't mean anything to cold startup (I can vouch for this, I froze my bare hand to my exhaust manifold once and the car had to run for a few seconds before I could get my hand free... long, awkward, painful story...) - let's just step back from this and not argue the point that for whatever reason, accounting for whatever variables, Jarrod's car starts in the cold every time. So does mine, without the preheater, but then it only gets down below -30C a handful of times a year here.
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Chris, Dartmouth NS Canada 70 M-B 280SE, 83 245DL, 84 244 turbo, 90 780 turbo, 92 VW Golf, 90 740 Rex/Regina