I fully understand you wanting to change the wires after 13 years, the heat has probably got to them a bit by now. As you can tell I practically live in mine as a daily driver so the miles add up faster. The plugs are a judgement call and you could play it safe and change them or if you want to reduce labor and time costs pull one plug that's easy to get to and check it's condition. With 56K miles if one is OK the rest should be as well. Please don't forget the copper anti seize lube when you put the new plugs in to be kind to the aluminum heads.

Good luck and take your time....

P.S.

If you plan to do the work yourself consider removing the inner wheelwell liners to replace the plugs and wires. I know this sounds like a lot of work and the hard way but having tried it both ways you can have the liners out and back in about 30 minutes, much faster than trying to get to the back plugs especially on the passenger side.