is there a difference between stock and aftermarket intercooler(front mount).Im thinking of buying a grand national i just looked at.I noticed the car had a stock intercooler on it.I asked the owner why he didnt upgrade to a aftermarket IC ,he said there is not much difference between the two.what`s your guys opinions about this???the car has a t-67 turbo on it.He claims the car makes 500 hp.