Roger Lee

So I'm totally confused.  I live in Vegas and it's hot hot hot.  I have a 2012 CTLSi.  I want to purchase the larger oil cooler but not sure who I could purchase it from and what part(s) and/or part numbers I'd need to provide the vendor.  I have a local mechanic on the field that will install much cheaper than the local shop.  He only charges $35 per hour instead of $105.  How do I purchase the proper cooler and what information would I need to provide in order to do so, so I can have my mechanic install?  Thank you!