Originally Posted by StephenVA

The recommended gap size is .032" for your application 05 BMW X5 3.0 engine
Use a fine wire gapping tool like the round one shown or a Bosch gap tool that has the calibrations for all applications.
As the gap wears, the energy to jump a wider gap is higher causing coil saturation (dwell time) to be higher, and the length of burn time as measured in mill secs, is shorter. All have consequences. Examples can be poor idle stability, tip in acceleration stumbles, high load (going up a hill) misfires. All will heat up plug wear, heat up coils, and shorten ign system life.
Bottom Line: Replace plugs as often as driving cycles demand 40-80k and use a little (a dot) Anti-seize on the treads, add a little Di-electric gel on the boot end that snaps on the plug. This two step will allow you to remove the coil and plugs in the future as well as locking out moisture. Too much product is NOT better.
Plug manufacturers add a coating to some plugs to reduce the metal to metal transfers that happen when you screw in different materials together. Threaded Steel plug shells to aluminum heads for example. Adding a dot of anti-seize to the threads only enhances the abilty to seperate these two items in the future.
Oh add a little anti-seize to the back side of your alloy wheels will allow you to easily remove them for their annual cleanings, wash, IronX, clayings, and waxing too!