I've had these on my car for 4 months. You can see my website for install pics (see signature). They DO NOT leak, not even a bit. They also have a 4 year warrantee if they ever do leak. These things are WAY COOl - open headers in 1.5 seconds from the driver's seat.
I received an e-mail from Summit Racing this week that indicated that the DMH Performance cutouts would be in their new catalog. You might want to call Summit for pricing before you get a GP started.