Make sure they thoroughly inspect for ANY signs of transmission leaks and also pull the lower chassis cover to inspect the transmission mount. The stock tranny mounts are lame and prone to failure. Once they fail, the entire trans starts flopping around, causing the transfer case to flex and the transfer case to trans housing gasket to fail. Ask me how I know...
Porsche doesn't offer ANY replacement parts for Tips other than fluid change related items. Sooo...dealer says "you need a new trans, that'll be $15k..."
The gasket is available aftermarket, but good luck finding a Porsche dealer or indy shop willing to do the gasket replacement / repair. I ended up doing the repair myself and changed the fluid as well. Local dealer Reeves was willing to do it for $2k, which I thought was extremely reasonable.