To upgrade intake manifold on not?

Performer RPM over the LD340 because the runner shape is more conducive to maintaining velocity.
Since the throttle will rarely be at or near fully wide open, the Performer you own is probably not hurting.
Not a fan of the Ed 750 unless the boosters are extended and the tubes checked and fixed if needed.

PS the shorty TTIs are a royal PIA on the driver side.