I have used both Fast Intentions and Z1 Oil Cooler Kits......both are good quality. Dont waste ur time with the 19 row. ...25-34 is where u wanna go....size will depend on ur weather conditions and how hard u track/drive ur car. I initially did 25 row Z1....but after tracking the car I found myself having to cool the car dwn a little before going back out again.....25 ROW would be good for daily and some spirited driving with very mild tracking in hot weather.
Then again I live in an area with tropical hot and humid weather year round....so upgraded to FI's 34 ROW and happy with it. I can do back to back non stop track runs and the oil temp never goes past 200°
As far as install in the Nismo....Vipor did a very good DIY......and yes u will have to flip ur Damper upside dwn for the 34 row to fit.
Here's Viper ' s thread
DIY: Oil Cooler Installation on a Nismo (Damper Included!) - vipor