until he or you know exactly how the system works don't rip it out
the system works just fine, you have maybe 1/4 hp parasitic loss from
it maybe weighs 5 pounds at most
it keeps the cat from being clogged
Generally I've heard it's a royal pain in the ass to replace with very little reward.
If he is going to road course race it then he might wanna remove the whole system and go with them open all the time with Pineapple Racing sleeves - but he should only do that in this one case.
With ports always open your low end power/torque is non existent.
Everything RX-7 wise has been cover at RX7club I don't how many thousands of times, so with a week or 2 of researching he could find the answers to everything.
Just don't go pulling stuff off the car, alot of the plastic stuff under the hood is quite brittle with age - trust me.

Really for the NA FC's money is best spent on suspension and tires rather than power, and then reliabilty stuff.
Ask me how I know....(See TR garage)