Before you go real far, what are the trouble codes or which cylinder is causing the problem? There is no need changing all the coils if only one is bad. If there are no trouble codes, it may be worth an hours labor at the dealer to find which cylinder is missing then do the work yourself. Simple tools are needed to replace the parts. A 7mm socket to remove the coils and a spark plug socket and ratchet. Just take your time cause some of the plugs are kinda hard to get to.