You need a router, it will open up your wood working immensely concerning plywood, really hard to work plywood with hand planes, its just not meant for that. The bosch is a great unit. You don't need a plunge router for through dados and grooves, but its handy for other things, so if I were to own just one router it would be a plunge router, but fixed base generally have a lower handle position/center of gravity, so I find them easier to control for grooves. Do practice on scraps as suggested, keep both hands on the wheel, if the router gets the idea for in a second that you are not firmly in control the little gremlin inside will take over and make a left turn, which can get expensive and dangerous. Remember, few things happen in a single pass with a router...small bites, sharp bits. And get a book by Pat, or take a class on routers, its amazing what some people get out of them with a bit of ingenuity.
"A good miter set up is like yoga pants: it makes everyone's butts look good." Prashun Patel