Indeed, sounds good.
But the problem is the short runner, ie the distance to the intake port on the head from where the air first enters the system.
Hence the likes of the TPI which has those curved runners on the side. The air enters the plenum, then goes down the runner on say the left continues through the intake manifold to the head on the right (ie the opposite side) thus giving a 17" (iirc) runner length in total. This gives a hiuge increase in mid range torque, at the expense of the ability to rev past 4,500rpm though. Changing to a short runner system, say a 5 inch length like the Stealth or Mini Ram, loses that chunk of torque in the mid-range, but can then rev happily to 6 grand with the end result being more horsepower.
The Caddy is a heavy car so you want low and mid range torque more than high rpm hp I would have thought. (I'm no expert mind)
The TPI system is actually quite trick because when the intake valve closes the wave of air (in effect) bounces back up the tube to teh plenum forcing more air down the tube on the opposite side of the plenum, which just happens to be the next cylinder that is filling. Devious.
