I have the 03.5 6mt sedan. I have the Stillen exhaust on my car and I think I am ready for more power. From what I can gather, this would be my next step (not going FI). But I am confused as to which spacer I should go with. I do live in NorthWest Indiana so it does get cold here. I will be going with the Copper Iso Thermal Spacer, but I don't know which one to go with. The 5/16 or the 1/2. I know that the 1/2 give 1-2 more hp at peak but which one would give the best overall gain throughout the RPM band and which one gives the best TQ as well. I have reviewed the motordyne dyno charts, but those are on the 287 hp 350z. From those in the audience that has the Motordyne, can you give me your opinions and or facts as to which one I should go for?

Thanks

Can you also please list your experiences with your MD Spacer? Good, bad, no difference?

 

No documented differences between the two. Either one.

 

Both spacers are really worth the $. I'm using their
1/2" spacer and love the H.P. and the crazy sound
at 3,500 rpm+. With a good cat-back and filter
(Stillen here) it really comes alive!