The core is just sitting in there, there is no way it going anywhere. I'd recommend a 24x6x2.75" core and keep in mind that will still require a lot of trimming, however the bumper support wont need any trimming

 

where did you get your ic piping from tom?

 

Here's mine at night. I still haven't taken too many daytime pics since I scratched the bumper to hell.
GReddy fmic kit- A total pita to install on the 2000. Especially when I had to take out my smog pump and make a new mounting bracket because the ic piping was going right into the pump.

 

the EVO FMIC does require cutting of the front bumper I put mine in not to long ago and wow there was no way that was going back on without some major trimming they should definetly change there website about that I would take some pics but I'm to lasy right now

 

here is mine

 

what kind is that Jeff ?

 

greddy