Yes you can replace your IM3103 with an IM3303 and use the existing speakers; 3 hurdles you will face..... 1) The new intercom master is smaller, you will definitely have to do some wall repair. Nutone does not make a finish frame that covers that old model intercom hole. 2) You must replace the housing in the wall.Obviously the old one is way too big... The new one is an IR104. (Make sure you order one because you WILL need it.) The new intercom uses 2 transformers instead of one. So as you are preparing to mount the new rough-in you will need a piece of 14gauge 2 conductor w/ground electrical wire about 2-3 feet long..(enough to get from transformer box to the other) The transformers come in the IR104 rough-in along with 2 boxes to mount the transformers into, then into the rough-in, and an antenna which you should not need. Just make sure before you mount the new rough-in box (slide it up and down in the wall)to make sure that all wires are long enough to hook to the new terminal board that comes in the master unit. 3) Your old speakers will undoubtedly have bad (noisy) controls because of age, and dust in the walls; so when you begin using the new system they will annoy you. Get some good tuner cleaner (a type that leaves no gunky residue)and be prepared to clean at least a couple of them if not all. Make sure you take them off the wall to clean the volume controls. If you spray cleaner through holes in the speaker the cleaner will soak into and dis-color your walls or damage your wallpaper. For your information the new intercom master has higher wattage output. Your IM3103 has about 3 watts; the IM3303 has 15 watts. This will eventually take a toll on your old speakers. The new ones have different volume controls to match... But it will work with the old ones, maybe for years...who knows? This should get you through the process almost painlessly...Have a ball, Terry

YES! Same speaker cone and same control as new speakers.