forget that pulling the plenum involves pulling many hoses that are brittle from age and heat. Some of these hoses are VERY pricey for what they are. Not to mention a few assorted gaskets.
I've done both, and the dremel method is the way to go for a single injector replacement. Needle nose pliers can help in some instances to "break" loose the screws prior to using the phillips or impact driver. Also consider soaking the whole thing in PB Blaster the night before you plan to tackle it.