Roof spoiler effectiveness

[Eatoniashoprat]

This has been touched on before, but I'd like a recap if possible .

At what speeds should one start considering this? 130mph+? What about a car that may only see street/strip? Can anyone attest to its effectiveness?


I'm building a ~250hp subaru 1302 and enjoy accelerating more than high speeds but I may not be able to help reaching 120-130mph on occasion. Would a roof spoiler be effective in this case? I don't want a wing or a front spoiler. The car will sit as low as possible. Would a roof spoiler make me that much safer at 120mph that it would justify me buying one? If I was unsure I would just go ahead and get one but I would rather not disrupt the nice roof lines if I don't have to. I also don't want my back tires to pass my front tires at high speed (low speed that's ok ) Help?