I'm almost certainly going to add a fan to my '07 525, it has overheated more than once. There seem to be two styles of fans available, one that incudes a shroud and fastens via the shroud to the radiator frame; and one w/o the shroud that fastens with little pastic ties that pass through the radiator. Shrouded fans would likely be more efficient when running, but when off, the shroud seems to my eye to lessen 'natural' airflow through the radiator, thus causing it to run more often(and load the puny 20W DC System more often) than the un-shrouded. The unshrouded fan, tho' less efficient when running, has perhaps a far lesser restrictive effect on the 'natural' flow of air through the radiator, but the mouting -- the four plastic items that secure the fan to the radiator fins -- strikes me as half-assed, and perhaps injurious to the radiator over time. Comments? I gotta order before the seriously hot Florida arrives.