terrapin

The original radiator in my car has two small leaks that surfaced after I flushed it a few times when I purchased the car. I would like to order a new radiator today, but do not know if I should go 4 core brass/copper or 2 core aluminum I have factory AC and Heavy Duty cooling as well. The link attached shows a few of the options I am given

Thanks
Ed

http://www.radiatorexpress.com/part_lookup.asp