[Paul]

From wikipedia:

All 986 and 987 Boxsters use the M96, a water-cooled, horizontally opposed ("flat"), six-cylinder engine. It was Porsche's first water-cooled non-front engine. In the Boxster, it is placed mid-engine, while in the 911, rear-engine. The flat, mid-engine layout provides a low center of gravity, near-perfect weight distribution, and neutral handling. The engines had a number of failures, resulting in cracked or slipped cylinder liners, which were resolved by a minor redesign and better control of the casting process in late 1999. A failure for these early engines was a spate of porous engine blocks, as the manufacturer had difficulty in the casting process. In addition to causing problems with coolant and oil systems mingling fluids, it also resulted in Porsche's decision to repair faulty engines by boring out the cast sleeves on the cylinders where defects were noted in production and inserting new sleeves rather than scrapping the engine block. Normally, the cylinder walls are cast at the same time as the rest of the engine, this being the reason for adopting the casting technolog