hey i was wondering can that be taken out if i was to make a custom plenum for it???

Yep they can, just need to weld the holes up on the outside

ok does it make much of a change

On my brother in law's CA we simply tapped thread and turned capscrews in there with some Locktite to keep them in place. Works a treat and no warped intake because of welding...

i was thinking of that just wanted to hear it from someone else

Hey mate, do you have a reason for wanting to pull them out? Is it not functioning properly? Have a read of the post on nissansilvia.com showing some back to back dyno testing of the valves held in different positions. Pulling them out would show a slightly worse readings in the lower rpm's as you inlet velocities would bit slightly lower. http://www.nissansilvia.com/forums/index.php?showtopic=365186