Also, I believe that it might have a function similar to the Mugen wing, and disrupt the vacuum that forms behind a car when it travels...

I'd say get a stock GS-R spoiler... I like the look of it on mine. I mean the things are probably all cosmetic, but I like the look of a small, minimal spoiler on sporty cars... I think Integra coupes without spoilers look a little too... unfinished IMO