has anyone seen any gains or noticeable difference in the z1motorsports power pack ported Upper Plenum?

Is it worth it or not. I was debating on purchasing this as a core and sending my back in return then getting the refund. I have not seen much research on google

 

I would suggest having both lower and upper ported. This mod is great when you have all the bolt-ons (Exhaust - Intake - Test pipe or headers and UPREV). This is not worth it if you are near stock and would need some tune to squeeze more power out of it.

I made near 320hp on E85 with full bolts on + ported manifolds (done by somebody else)