road trip - rent or take the X5?

[c4racer]

We are planning a long distance road trip over the holidays to visit my parents in Portland OR and driving from the SF Bay Area. It's about 750 miles one way. I was planning to drive the X5 up in case we ran into any snow.

But just for grins I checking into rentals and I could rent a full sized car from Enterprise - Altima, Impala or Charger - for $200 for the week. Which would save me at least half of that in gas costs alone. So for $100 to save the wear and tear on the X5 may be worth it. X5 is racking up more miles this year anyway with my wife driving it for school car pool runs - I expect to do about 16K on it vs. 11K last year. On the other hand, what's another 1500 miles, right? I am slightly worried that I haven't swapped out the cooling system yet - I have all the parts to do the job but don't want to do that right before a long road trip. Been checking and all looks good. Expansion tank and upper rad hose were replaced 25K miles ago, but the radiator and water pump are originals. Tho I guess cooling system wouldn't be too taxed this time of year.

I just swapped on the winter tires and new brakes front and rear and planning an oil change this weekend. All service is up to date, even fresh fuel filter. So she's perfectly road worthy.

Of course I will be kicking myself if we take a rental and then end up hitting snow..... And the X5 would be a way nicer long distance road trip car. But damn the rental is so cheap it makes me think about giving the BMW a rest for the holidays!!

Thoughts?