Looks like you need to remove the intake manifold. Doesn't look too difficult, but you should probably use new gaskets on the manifold at the heads when replacing it. Should be a case of opening all the associated electrical connectors, pulling off the vacuum tubes at convenient places, disconnecting the air intake, and then simply unbolt the manifold, and probaly swing it up to the right. I'm estimating a couple of hours to get it off the first time, taking it easy to ensure everything is disconnected & can be moved out of the way. I have 23K miles to go before I need to do this, but will post on the experience.
There is an enthusiast forum called www.imazda.com with a procedure on how to do this task. I used it to perform the job on my vehicle and it was accurate. It is in the engine / drivetrain section. It does involve removal of the intake manifold; however, with patience and attention to the task you can do this without completely removing the manifold from the engine. There are wiring harnesses that attach to the intake that you will need to be sure to get loose so you can manipulate the manifold. There are eight to ten 10mm bolts that hold it down. Rory