you really just need to take into consideration the design(tube and fin, or bar and plate), and the pressure drop in the intercooler, bar and plate are known for higher flow rates and less pressure drop but are a little more expensive, but well worth it.....and to give you an example, alot of people with subaru's including when i had mine bought the ebay intercooler that was 300 bucks instead of the 1200 turbo xs or perrin ones and made just as much power and were just as happy with there purchase.....