I just installed a 34 row from Z1 a couple weeks ago. 2014 Touring/Sport, essentially stock, my DD and autocross/HPDE warrior.
I left the stock oil to water cooler because I didn't have the non-cooler filter stud. If you leave the stock cooler, you will have a tough time getting the lines installed and the oil filter in place. There is very little room for the tiny stock filter with the Z1 cooler plate and the stock cooler plate installed; forget about putting a taller filter there. I am going to remove the stock cooler soon and bypass the coolant loop.
I ran a track event in NC last weekend, with temps around 95 and ridiculous humidity. Oil temperature topped out around 230 during each 20 minute session, and quickly dropped to 180 after coming off track and turning the A/C on. I was trying to keep up with the C6s in the twisties and keep the STIs in the rearwiew, so I was not being easy on it at all
