Which cold air intake?

Nixin

Cool thing about the Z1 is that you do not have to cut anything to instal them. The Z1 CAI is not necessarily cheaper, it's just more affordable than some of the others.

Jhill

Yes but you only get the max gains they claim if you do cut the radiator support, so now your back to the same as Stillen G3. I went G3, enough people have them with no issues and your only trimming a very minor portion of the support that wouldn't even be noticeable if you went back to Oem.

NRGz

This.
This was my issue when I was looking for an intake. Removing the bumper is fast and easy. The cutting/trimming was very easy as well. I used a small dremel tool to cut and you only remove so much of the support. I like how the intake sits as well- behind the bumper. Gives the inside a more cleaner look imo. You can also hear the air being sucked in, into the intake.. Sort of like air going through a metal piping. Just had to zip tie some areas near the filters so there would be no shaking and rattling.
+1 on the G3. Smog legal as well if it suits you.

Thyristor

I prefer the Nismo R-Tune intakes over the ones listed. They look fantastic and seeing the word Nismo in my engine bay makes me that much more happy. No cutting required either just a bit of drilling to relocate the windshield washer reservoir.