Are there any differences between any of them?

I really dont think so... All i remeber is z1's could have been a bit longer on the passenger side. The hps fit spot on

Mmmmm? I'm not sure. Maybe a little. Such things have can have a placebo effect. I put these on shortly after I installed a F.I. CBE so I attributed most of the improvement to the exhaust. I did the intake tubes to clean up the engine bay and make it look better. I bought the side tubes (see pic on my earlier post) to get rid of those ugle little oil-catch boxes that I'm told do absolutely nothing on a non-turbocharged engine.

I also keep all the old OEM parts in case I ever sell the car and someone wants it put back to stock. "Here's the parts...knock yourself out!"

the mishimoto fit really bad on the passenger side.. have them on my car

Z1 doesn't have steel wire inside to keep the shape so under WOT the tube doesn't collapse. I don't think it's a issue because it's really thick silicone. HPS I believe does have the steel wire. Only difference I know of.

That is correct on both, the hps is imho the way to go

Im curious about mishimoto... Hps>z1

I assume you meant to say the Z1 DOES have steel wire inside. Their description on their website says it does, so I would think these are the same as the HPS...

Question for you. I just bought the Z1's to replace my HPS tubes and I bought the Silicone tubes for the breather pieces. I read some people having fitment issues with the passenger breather tube being crimped when installing. Did you have this problem?

I bought these to replace the HPS becuase the driver side plastic baffle piece cracked in half and I wasnt sure how to fix it, so decided to replace with post MAF tubes and the PCV Breathers...

When I had mine installed it didnt crimp. There are many ways to do it, one of the small connecter pieces could be used which makes it a bit contorted, also the MAF tubes can be rotated as well to make it easier.

i had to cut my z1 just to fit. I can assure you there was no metal wiring anywere in the contruct of the tube its just rubber

It does have metal wiring actually. And they dont need to be cut to fit. They are a tight fit, but thats a good thing.

when I sliced into it there was NONE....unless its deeper or closer to the center. either way I sold them

This is what they say on their website:

"Produced in a multi-layer, wire reinforced silicone, these will never deteriorate, crack or degrade over time as a result to their exposure to heat, chemicals or debris (...unlike the factory rubber hoses which will eventually fail!)

I actually wouldnt have thought the HPS have wires either. When I installed those, I didnt take out the airboxes or the strut bar. It was quite the challenge but I bent those things up every way possible to squeeze them on, they snapped back into shape right away. I would think if they had metal in them they would stay somewhat bent...

But now that im looking into it, i don't see anywhere stating that the HPS tubes are reinforced with wire...

I would have thought rotating the tube to make everything fit would work also.

I wonder if anyone else has dynod these besides me like 4 years ago lol