The GT40 guys pretty much have determined, through flow studies, that a 1.5" diameter path, with smooth bends, along the length of a Mirage's length, is doable. When you start adding the abrupt corners or ends to the mix, then you may get reduced flows. Based on their data and discussions, I think a stock pump should be able to continue to push sufficient coolant through the system. I use an inline pump that has more capacity than i need. It is a 55 GPM, is a bit of overkill, but it is good insurance.