I run forges R26 360bhp/340 torque, no problem with oil temp, as I also run an oil cooler. The only problem I had was the failure of 2 turbos, turned out they were Chinese copies, from a well known tuner. A different gentleman had a forged engine built, it blew up, when inspected by an Engineer, turned out, it was standard, and never been forged!.I now run a proper garret turbo, and never had anymore problems. No, I won't name the tuner, as I am too old to get into a fight on social media!!.