Depends on how old your truck is. If you have a newer truck you may find an older 5er will not fit without expensive lifting modifications.
I don't see lightweight as being the enemy if engineered correctly. I prefer to look for products that have safety margins with their frame capacities and running gear. My trailer axles and tires have capacity safety margins of 42% and 36% respectively. After following this forum for a while I conclude there are many failures due to people running things right to the edge of their specs. "Can't understand why my tires failed, I was 6 pounds under max capacity". Look underneath. A manufacturer that over engineers their running gear will probably be conscientious elsewhere.