I run the same style exhaust on my Z10. The down and back header style header in the style that seems to work with most Z10 tail bodywork combinations. I inquired about the configuration when I rebuilt the car and was told by an engine builder not to alter it because the combination of the primary tube length/size with the collector/tail pipe length size was done on purpose. The only way to get the tail pipe long enough was to run it transverse tight to the gearbox and exit out the other side of the car. The headers that use the longer tail pipe seem to have a larger diameter and shorter primary tubes as compared to the straight back model. It seems to be a function of exhaust tuning for a usable power curve, not sound. If anyone else can shed some light on the subject jump in here.