I will pose a baffling question. I have a 328GTS that needed a clutch. I had an IFS do the job. I got the car back and realized an oil leak coming out of the bellhousing. The shop took the car back ansd replaced all o'rings. In addition they removed the flywheel and replaced the rear main. The car leaked again after prolonged highway running. They did the entire process over again. Ran the car for an hour, no leak. I drove the car on the highway for 100 miles. Same leak began to appear. The shop is now investigating pressure buildup in the engine causing oil to be forced past the main. This shop incidentally performed the entire 30k service at the same time. The car has 20k miles. Has never been a leaker. Any thoughts on what they are missing?