MTM has an RS4 B7 CF hood with vents on it, perhaps you could have a look into it and apply it on your particular case. I guess you could also replace de SMIC with a larger FMIC and leave the side vents clear for better cooling, underbody panels are also a good place to start looking into.

Good luck!

Just remembered, I once say a pretty cool mod on a Mk4 GTI/A3. As you know the SMIC is isually blocked in the back by the "fender liner"(dunno the specific name) but, these guys cut it out and placed on of those bathroom vents in it, of course good materials, fit and finish are a must, but apparently it worked like a charm...I believe I saw that in vwvortex.