I'm in the exact same situation because my car was an AT before and I left the stock radiator on the car. I usually am around 176-185F for regular driving and never have seen it pass 206F whether beating on it or sitting in traffic on a really hot lower NY day with the AC on. I have an STi EJ207 if that makes a difference. This is taken from the ECU's sensor with a max record function of the PSi3 SECS unit.