and I/C will greatly reduse your intake tems, but won't have much efect on your engine timps except maybe at WOT, as for plumbing the I/C, I'd get an I/C with 2.5" inlet and outlet, plumb the 2" form the hotside to it with an adapter at the I/C then plumb 2.5" back to the TB, the TB is only 2.5"and I'm unaware of what might plug intot he stock piping between the turbo and TB but I assume your it's not needed, if you wanted you could always tap the new piping and thread in a barb adapter
as for the BOV, when your shift gears you let off the gas, the throttle slams shut and all that boosted air pushes against the TB and then backs up to the turbo, this is bad for the turbo but at stock boost levels not a real big deal, the BOV lets this air out and depending on the type of BOV either vents to atmosphere or recirculates it back to between the MAS and turbo to be used again, with stock engine managment you want the recirc type or it'll cause a momentary rich condition followed byt a lean conditions as your ecu tries to correct
the advantage to and I/C is you can run more boost, if you plan to run extra boost the BOV si a good idea to protect the life of your turbo
now about htat VG sandrail, lets have some pic's 
"if I had all the money I ever spent on cars........I'd spend it all on cars"
12.378 in a rusty datsun with a sliping clutch
"The Rusty Mistress" 299.3 whp and 305 lbft TQ, 2105 lbs
I'm cleaning out my garage, lots fo Z parts, S30, Z31 and Z32 here is my ebay listing
http://motors.search.ebay.com/_W0QQsassZevildky
if you're looking for something shoot me an e-mail, evildky@bellsouth.net
