Pressure and heat won't be a problem I can gaurantee you that, they hold over 100psi with the system not running, and are drawn down to the 50-60s with it running and in AZ with the AC on full, I'm sure they heat soak to well over 200° and they're usually solid copper tubing with decent brazing work.
As for the flow, that is going to be your hang-up. I'm rather sure that internally they're not going to be more than 3/8" tubing, which is quite small for an inline oil cooler.