Coolant tank developed a tiny crack at 63000 miles and was leaking coolant. Purchased a new $120 tank on eBay and installed it myself, which took about 6 hours; not an easy job because the tank would slide out easy, but won't go in. A very common problem for the 996.
Ignition switch went bad at 65000 miles, Porsche upgraded the switch, but I found a new original switch on eBay for $20; same as Audi/Passat switch, and installed it in less than an hour using a tiny screw driver. Dealer won't replace the switch, they charge $1200 to replace the whole lock cylinder and upgraded switch.
Remote key no longer works, and the key needs a new program code at the dealer. The rear tires last 8000-10000 miles due to rear wheel and engine, and are expensive.
But overall it's a reliable car, and it's my daily driver.