Well I have started to mock up.
IMO Pros:
-'clean' airflow while moving
-airflow if the radiator fan is on while sitting stationary
IMO Cons:
-partial blockage of the radiator airflow which may not be an issue depending upon the ambient air temperature
-heat exchanger in contact with the radiator may cause some heat transfer if no airflow
-may require some fabrication of a mount (plastic through the cooling fins mounts are not recommended)
This configuration will get better heat exchanger cooling than the stock mounting location behind the radiator. Be sure to share your experience with this mounting configuration.