With the way you waste $ switching cars every year I'm not sure how you can afford a house. None of my business but I doubt you'll be happy with a Z this time around. Just buy used.
Anyway...
Can someone tell me if there is an oil cooler on a 2012: Yes
What other changes were made since 2009: Several, mostly minor including a cabin air filter and heated mirrors
What is a good price on this car: Research!
New Cars, Used Cars, Car Reviews and Pricing - Edmunds.com,
Hassle-Free Car Buying Experience from Local Dealers - TrueCar, etc
There is a search function here I suggest you give it a try.