DIY oil cooler is on the way.
CORE: I decided to start with the Tru-cool 24 row oil cooler for now. I only have 1 track day planned for the car; if I end up getting hooked, I can easy upgrade the core. If I decide that the track is not my thing, the small core will definitely suffice for street driving. I will try to take on M.Bonanni's idea, using a shroud surrounding the core to see if it helps with directing airflow.
OIL SANDWICH PLATE: Since the car is not daily driven, and I'm in the TX heat, I decided to go with a non thermostatic oil sandwich plate. It freezes down here for a week or 2 tops. Not an issue for me.
OIL LINES: For the lines, I went with 1/2" hose and -10 fittings, but I had them made today, locally, at a hydraulic shop. They had them ready 10 minutes after I ordered them on site. Thanks to 370z.com member 'Mike' for the idea.
Don't mind my SSR table 
All in all, I think I made out pretty well. The oil cooler, sandwich plate, and 3 fittings (they were out of stock on 1 90degree 1/2" fitting) ran me $96 from racerpartswholesale. The local lines and the 1 missing fitting ran me around $110. All I need is a sheet of metal for the bracket (which I have already in the garage), and some aluminum sheets/tape for the shroud. I like the idea of a $215 budget oil cooler, brand new.
BTW, if I were to buy 10ft of -10 line, 4 fittings, and shipping from summit, it would have ran me $119. Plus I can skip assembly of the lines, not worry about stainless lines eating through anything, and have the peace of mind that these hydraulic hoses will handle the oil pressure that this motor creates.
Hopefully all goes smooth over the next 2 weeks during the install