On BMW V8 engines the valve cover gaskets are a tremendous pain in the ass. At least on the N62 and newer engines. I would NOT attempt this at home. There are many specialty tools needed that most people don't have, and you could get yourself in a bind if you break something. Also, the upper timing case covers need to be resealed when you do the valve cover gaskets. These can add to the headaches. The N62 has many things that make it a pain in the ass. There are small torx bolts on top that like to strip. The E60 and E63 need to have the engine jacked up on the passenger side to be able to remove the rear ignition coil (on cylinder 4) before the bank 1 valve cover is removed. The gasket itself turns into hard plastic and sticks to the cylinder head, making it really hard to separate the valve cover gasket from the cylinder head. The spark plug tubes also contribute to this and make removing the valve cover from the cylinder head very difficult. Once you have the valve cover loose it's still a pain in the ass to maneuver it to remove it from the engine. If you force the valve cover too much at an angle you can break the eccentric shaft sensor on the back of the head. Those sensors are about $500. Once you have the valve cover out, you need to take the timing case covers off. On the driver's side (bank 2) you need to remove the alternator to be able to do it, and the vacuum pump on the passenger side, which requires skill to put back on. Oh, and you need a new one of those pumps too since they are notorious for leaking. The pump is about $600, but you can't buy the o ring that causes the leak. Then you need to replace the vacuum hose that goes to the front of the vacuum pump. It gets brittle, and once you remove it to replace the vacuum pump it will not go back on and stay there. It will break off and cause the engine to sound like a turkey. This job, to be done right, requires a lot of skill and patience. If you need this done make sure you get someone that knows what they're doing.