Peter is right, there is so much more testing behind the Dinan design it has more to do with how they are tailored to the S62 than just opening up more space for airflow. In an old interview with Steve Dinan, he even said their first attempt was to just enlarge the stock system and it lost power across the board. They slightly modified the shape of the intake runners and while not carbon fiber such as Peter's, had great success there. The length of the runner generally determines torque, while also protecting the natural valve resonance of the engine's harmonics. Resonance is less a factor in an ITB car than a single throttle car with one big manifold but it can still be tuned somewhat!
If cost is an issue, best bet is to shorten the stock runners by hand while retaining some of the overall shape. A few high hp engines out there have this design. If you want to go one step above that, but a step below the superior Dinan/Peter design, Wilson Manifolds could help enlarge the stock TBs but you'd be on your own for trumpets!
Also, maybe Peter will make some of these in aluminum for all of us general public folk! Will stay tuned! 😛