I'm not sure why you choose the sport version of one spring and the race version of the other. Really both race and sport version of both these spring companies are the same thing. Since you want to go low you want the Race version from either company. In terms of price go for which ever one is...
I think the whirr is normal do to the fidanza. As to the higher idle at start up I don't think thats normal. Not sure why it would be doing that though.
Re: 1SICKv6 (Orange coupe)
Nice looking show car bro. I can tell you put a lot of time/money into it. How many trophies have you got so far? Also could you post up a picture of your engine bay?