I myself am looking into getting a set of sards vg's for my s14.. much more functional than a roof spoiler. Might get a APR spoiler later on to help with its function
I am still trying to find out how to best place these without having to rent out a wind tunnel.
here is quite a few placed on a RD.... rather extreme FD
but buy the looks of the wing height in the sards image... doesn't look like it needs to sit up there that high *the actual wing*
sards are a bit bigger than the oem evo or the chargespeed one's being sold right now.