oil separator symptoms

[dinan6]

I live in fairly cold country (Northern NV) and am planning to purchase a used 2002 or 2003 X5 with the 4.4 V8 engine. Since this car may spend a number of nights outside in the winter cold, is there a certain low temperature at which I should retrofit the engine with the insulated Oil Separator and the electric heat blanket? It's sort of a pricey and Rube Goldberg retrofit, so I don't want to do it unless the mod kit is really needed.

For example, are the improved parts needed with night time lows of 20F? What about 5F or 10F or 15F? We regularly see winter night time lows in the teens around here. I had an experienced mechanic around here tell me that he didn't think the improved parts were needed, but the last time I checked, a car sitting outside and not operated for several days will get pretty cold, especially if daytime temps stay below freezing. So I am leery of blindly following his advice. What is the experience and recommendations of the forum members on this subject (for the nighttime temps I have noted above)? Thanks.