The author upgrades a 1610 (also can do 3018) to the size of a 5050, which is like 50 mm to 500mm. According to the author, it was cheaper than buying a 5050, and he did some other upgrades that are not on the standard 5050, so it seems like a good deal. Not sure on the cost difference thought. As far as I can tell, they all use the same spindle motor, so the swap should work out.
https://www.instructables.com/3018-CNC-Machine-Upgrade-to-5050-CNC-Machine/