Wouldn't that complicate piping design a bit in the sense that each bank would have to be matched about perfect. A 'normal' uppipe would be better IMHO, especially for duplication for some what mass production later on.

2005 Ford F150 SuperCab FX4 1964 Chevrolet Impala SS 1998 CSVT: 354HP/328TQ @ 10 psi, now gone