I recently got my hands on a used JR NA oil cooler. I was originally going to go with the RacerX one, but can't pass up a good deal when I see one. this was the reason why I removed the Grimspeed intake and the OEM style oil cooler earlier.
fortunately, I did not run into many problems when installing the oil cooler. however, I did need to buy the tools needed like the 27mm wrench and 27mm socket. I used the 27mm wrench on the female AN fittings as well, even though they were a 25mm wrench size. the most pain in the ass was to tighten the 27mm oil bypass. my socket had a slightly too thick of a wall so it was making contact with the sandwich plate. I just used my torque wrench and used one hand to force the socket on the 27mm hex and slowly (I mean VERY slowly) tightened it. it slipped a few times but hopefully I won't have to take it on or off any time soon.
I closely inspected for leaks since I didn't trust myself (lol) but so far there were none after a 10 minute drive. I'm going to keep checking over the next week just to make sure.
also, the oil lines ran pretty close to my stock intake box and I tried to give as much room as possible. hopefully there's nothing wrong with that since the space is extremely limited.
I was considering the Mishimoto and RacerX oil coolers since I wanted something to hard mount on instead of screwing through the plastic undertray. although people say it's no problem, it just feels pretty sketchy to me. I feel more at peace with the oil cooler mounted on a solid object (in this case, the bumper support).