I was looking at the 4" flared port tubes.

I don't know too much about them but how do you find tuning for your box with them?

And how much do they displace?

PSP Calculator This is the calculator I use for my ports. I have used both 6" and 4" versions of the Precision Port purchased from Parts Express. As far as displacement goes, I just estimate it calculating the volume of a cylinder equal to the length of the port I am using. It would be difficult to calculate exact displacement due to the flares, but this will get you close enough. Volume of a cylinder = (pi)r^2*h, where r=radius of the port and h=height/length of the port. Hope this helps.

ALOHA FROM HAWAII,

SKY