We were going to cut a matching hole for the dry sump pan in the 911R diffuser which would have messed up its effectiveness. However, the engine has a pretty effective water to oil cooler, and it’s a dry sump so not much oil is in there anyway.
One of our friends that has a 991.1 GT3 has added the 911R rear diffuser 18 months ago and has done numerous track days with no heating issues. Also, when we looked at a brand new 991.2 GT3s, we noticed that it did not have a hole either in its pan, so we decided to install the 911R diffuser as is with no hole.
As you can see the 911R diffuser is much bigger and covers more of the car’s bottom. The outer strakes cant outward to improve the diffusion ratio, making it more effective.