Just dropped my H off for 4th annual service. The service advisor told me they inspect plugs, and if needed the replacement labor is 16 hours! My car only has about 10k miles so I don't expect it to be needed, but still is it really that hard to get to? Is it really much more work than just taking off the CF engine bay panels? 16 hours seems like engine-out type of work. I haven't found a DIY guide on it yet.