it seems there are varying opinions around on them. places like HPF say they arent suited to the street becuase over time the water in the tank heats up and they've had trouble getting the heat out of it again (ie heat soak)
others campaign for W2A coolers saying that they dont suffer from heat soak like A2A do.
the secret, i believe, is in slowing the water down as it passes through the core and radiator, and allow time for the heat to really be transfered whered it needs to be. if you go ahead it with it, it could be something to try, fitting different restrictors on the water side, or even a tap somehwere in the system, that can adjust water flow to monitor inlet temps while on a dyno or something