Oil cooler horizontal/vertical matter?
 

Trying to determine available space and placement for an oil cooler next to a big intercooler. It looks like passenger side behind the bumper might work (saw on HKS site) but the radiator fins would need to run vertical rather than horizontal Does that affect performance in any way?

Heat dissipating wise - imho shouldn''t matter much except if at some position part of rad might be masked in some airflow deadspot. If it's high pressure oil pumped through, then bleeding/air pockets doubtfully an issue at different positions. I'd look only how secure is mounting in different mounting ways and how easy to route hoses at them.
P.S.
Take these words with grain of salt. I never had oil cooler yet, just shared my thoughts.

Which turbo kit? depending on how the intercooler pipes are routed you may be much better off putting one of these next to the intercooler. running the lines off of the side of an oil cooler is a huge pain in the ass unless it's mounted on the driver side.

Pic related. $225 core.