Im running open class already so production is out of the cars spec before i even took the project over
I think you missed my point..
NO matter what class you are in, seat time will do more than extra power. Another example, the Sprongl brothers were on the podium multiple times with a ~100hp suzuki swift (that was only ~3-4 years ago) at the national events. Mind you, those guys have crazy skills, but it proves that a lot of the current cars are not driven to their potential. Yes I understand money has a lot to do with it, but it's more about spending money wisely.
I went from an 02 wrx wagon (stage 2), to a 98 RS, basically chopped the hp in half. I find I am making less mistakes because it is forcing me to be smoother and plan ahead more.
Another consideration, is anti-lag isn't cheap. It is VERY hard on the engine/turbo/etc. So you maintenance costs will definitely go up.