Ok so I've narrowed down the spacer options.

3/8 powerlab

Or 5/8 skunk2
( this one doesn't come with the spacers to clear strut brace. Maybe I can use something else?

 

If you get a 5/8" spacer go with the BLOX over the SKUNK.

3/8" will give you more overall but 5/8" will give you more top end especially if you tune

5/8" won't work with the 350Z strut bar though...so if that is your factor I'd stick with the 5/16" from Motordyne or the 3/8" from PowerLab

 

Blox is half the price, why wouldn't the skunk be better?

 

^^ why not motordyne. Thats what I have on my Z. I like it. HP gains between the motordyne, skunk, powerlab are about the same. I have heard that the skunk keeps upper manifold temps cooler because of its composite material, but cant say for sure. That might give you another 1-2hp, maybe.

I would go with the powerlab between your two choices. HP between the PL and Skunk have to be within 1hp of each other but with powerlab you still get to keep the strut bar.

 

Cool thanks D and toll. Powerlab it is.

 

Just because price is higher/lower doesn't mean the higher one is better quality. The BLOX is made from a composite material which will actually prevent a lot of heat soak into the upper plenum AND it has supports for the 6 pillars that the Skunk2 doesnt have.