It depends. If subaru compete's against other cars in its "class" and gets whipped it will not look good. If they merely do ok, It will help some.
The problem is that the rules usualy dictate who wins, if the money doesn't. I HATE the people who bring up how well the Type-R does in the Speedvision series, when in its first year or two (the only years I paid attention) they had a HUGE advatage over the competiton due to the rules. No **** they will whip the BMWs when they have the same HP and are allowed to run 350lbs less weight.