yeah...
i'd be careful giving them money.
I haven't checked much into it, so maybe i'm mistaking here
but it seems some mods are converted from other games, so paying money for that could be called... fraudulish
edit:
example with the clio "MOD ripped from rF2. Fisica by" whoever
Every car I saw on that page is a rip. Pretty sure the GT6 comes from a mod for GTL or GTR2, so charging money for a ripped conversion is really tacky.