The spark plugs are a cake job. If I remember right I took the airbox out but not the battery. I do know it was like a 30 minute job for me - but I've been doing this for a couple days now....
Some of this stuff is overvalued by the book, but it helps out when something bites the mechanic in the butt, like rusty cars with bolts that break, stuff that someone else has fiddled with, etc., etc., etc.
If you've got a few tools and aren't prone to breaking things I'd give it a go if I were you. Pockets had the right attitude when he said he'd try it and wouldn't be embarrased to have it towed in if it didn't work out for him. Ends up he did a great job and saved a few pennies to boot.