Just went through this with my 1986 Spider: I replaced the hose without the restrictor and it didn't make any difference in this hot weather. Its supposed to be there to help the engine warm up faster. Since I drive the car all year, I decided to take the restrictor out of the old hose and install it in the new hose. I do remember the car warmed up quickly on cold days, not sure how the restrictor would affect the car until the weather cools down this winter- a few months from now.