Ok, lets say I build my sealed enclosure thats also in the size needed for a ported one as well...I go sealed for a while, and realize there's more that I need, before redesigning the entire box, would it be alright if I got some areo ports the correct length and diameter for that particular size enclosure, and run those? Just wondering, incase it comes down to it.

Also.....if I cant fit the 4" size it calls for, would 2 smaller ones do just as well?