So that means the 3.0 24v which should theoretically be able to suck in much more air through it's extra valves and increased displacement, can only breathe as well as the venerable 2.5 12v! Bet a few horses could be easily released from a later 24v simply by fitting it with a bigger plenum and trumpets which actually fit...
Finally, the common bits. Everything from the front end of a 12v will just bolt on to a later 24v; that came as a surprise too.
You'd probably get a few more horses but only at the top end. The 24v was tuned for a relatively flat torque curve to assist in low speed tractability. Narrower intake dimensions assist in low speed torque as airflow velocity is increased; of course at some point you restrict top end power. Increasing intake port diameter could actually reduce low speed torque.