Stop in for a cup of coffee

Mattax said
There will always be some increase in flow and reduction in flow and velocity. Whether it is enough to make a difference can probably only be discovered the hard way. In air-handling systems (in buildings) too much flex duct definately is a negative on efficiency and effectiveness.

Ribbed pipes reduce the flow to the minimum diameter of the ribs at the narrowest part of the ribbed section plus a significant amount more since the turbulence between the ribbed sections reduces the effective laminar flow region substantially. A ribbed coolant tube can have as little as 40% of the flow cross section flow of a smooth tube.

In other words, it can be like replacing a 3” diameter radiator hose with one that’s only 1.25” in diameter.