Doesn't greasecar use copper for the in-tank heat exchanger? And greasecar doesn't come with a final heat exchanger right before the IP. VO will polymerize more quickly if its in contact with copper or steel. Aluminum is a better choice.
I'm another frybrid fan. They use aluminum for the fuel lines, valve bodies, and heat exchangers. And they use the hose-in-hose style supply and return lines...which is better for heating the fuel than hose-on-hose. If you're careful with your installation (i.e. don't kink the aluminum fuel line when you're working with it), you'll have no problems.
I think you'll do better going to the
infopop,
greasecar, or
frybrid forums than here.