what brand and model intake would be best for my 2007 civic si? thank you.

 

if i were you, i wouldn't mod a 07 civic. those things are a lot better than the previous civics from factory, plus they're so new, the aftermarket support for them is very little right now

 

the aftermarket support is there.

as for a noteable CAI there is Injen, and AEM
as for SRi there is Injen, fujita, and k&n
i recommend injen for the CAI and fujita for the SRI
you just need to decide if you want a CAI or a sri

 

How much you want to spend, and how much power do you want?

I assume you daily drive the car, so no ITB's.
If you can get your hands on an IPS intake mani that would be sick.

Realistically though, Injen is the way to go for the new Si's. As much as I love AEM, their new intakes are pretty cheap and cheasy, and don't make as much power (or sound as nice) as the Injen offerings.