Correct. 15MM ratchet and box end wrench to remove them. You may have to grab the blower to rock the engine a bit to remove and reinstall the bolts.
We did plugs on an 04 GTP this weekend. Piece of cake.
fwiw I bought this tool take comes in handy, especially for the price. Amazon.com: Lisle Engine Tilter: Automotive
Something that no one ever mentions is setting the e-brake and putting the car in neutral before tilting the engine. The two tilter tools that I've seen, both recommend doing this on the GM FWD vehicles. One of the tilters has a warning label on the tool itself.
