BOV charge pipe (2" vs. 2.5")

[The_Producer]

Alrighty, I had a friend who was getting rid of his blitz super sound BOV off of his S13 Silvia, but anyway... my question is that the charge pipe that it is currently installed on is I beleive 2". Should I chop it off and mount or have someone mount the flange on a 2.5" charge pipe? I am only going to be running 7psi boost on a ZC engine. Any suggestions??? I am mainly asking because most of my piping from the turbo - intercooler and intercooler - manifold will be 2.5" I didn't want to interrpt the flow unless it won't make a difference, since it's forced induced airflow anyway. Let me know what you guys think I should do!! Thanks!!!
i APPRECIATE the help.

[PM-Performance]

if your gonna run 2.5 the rest of the pipes why would you keep[ the most important pipe 2 inch ?
BTW i wouldnt go any lower then 2.25 on upper change pips and outs of the ic, the lwoest i would say is 2inch on the turbo side.

[SuperStud]

no point in running 2.5 all the way then 2 right b4 the throttle body. that's like running a 3" exhaust with a 2" tip on the end.
it'll only flow as much as its smallest part

[The_Producer]

well that's what i figured, but he was convinced that it wouldnt make a difference on a turbo'd car. Just wanted to make sure because if I don't have to bring out the mig welder then i won't. it hates me for some reason.... (long story).

One last question... the air port on the BOV (i am assuming is a vac. line) goes where? Does that too tap into a vac. source on the wastegate or manifold?

[PM-Performance]

it really doesnt matter as long as it gets a vac source.

[The_Producer]

thanks, you guys rule

[iLLeFFeKt CiViC]

how big is the intercooler inlet and outlet?

[The_Producer]

2.5 on both sides