ya, rear facing scoop is almost always more functional...
it relieves heat from the motor, which is much more helpful than pushing in a bunch of dirt and bugs...

the only real function im aware of for a forward facing scoop is asthetics or if you have a top mount intercooler (like a subaru STI)
http://www.iwoc.co.uk/images/my2003/my03stiuk03.jpg

(ya that rediculously huge scoop on the STI actually has a purpose )