Originally Posted by Homemade WRX
They are both tri-y manifolds. The differences between them are primary and secondary lengths...I'm curious what the differences in primary and secondary diameter....as well as collector (uppipe section) diameter and length.
Those values will really tell you what RPM (resonance) the manifold was tuned, based on second or third wave reflective value.
I wish I had taken real measurements before I put the EBAY header in but I was in to much of a hurry. The up pipe was rather large tho