bout my rx7 turbo II a week or two ago, ordered an aftermarket BOV but dont know what piping i need? first time working on a turbo'd car.

 

a quick ebay search will show you tons of used pipes with bov's for a 2nd gen turbo. i found one in 10 seconds. here is the link:
http://www.ebay.com/itm/JDM-Blitz-SS-blow-off-valve-BOV-Mazda-FC3S-RX-7-13BT-Turbo-universal-type-kit-/181638199844?pt=Motors_Car_Truck_Parts_Accessories&hash=item2a4a7afa24&vxp=mtr
this is exactly the style pipe I've had on all my turbo II cars. i also have always used blitz bov on them. i would look for a pipe that is similar to this but make sure it is made to fit your style bov.