Let's take a 2009 Camry as an example. It runs on a 2.4l, 2360cc to be exact, engine with 4 cylinders. This means that the capacity of all the 4 cylinders combined would be around 2.4 litres in volume. I have noticed with Japanese cars after around 3.0L they add two more cylinders and make the engine a V6. Why can't you have a 3.0L I4? Or a 2.4L V6? How does it change the engine? I'm assuming that for a 3.0L I4 the cylinders would have to be larger to hold the extra volume. Would that mean that it would take them longer to burn the fuel inside and lead to slower acceleration maybe? Finally does it matter if the car is a 4WD or a 2WD?
You can have a 1.6 Litre V6 if you want - currently used in formula one... As to how it changes the engine the inherent balancing of inline 4, v4, V6's, inline 6, straight 8 or v8 does make a difference to how smooth the engine runs.
As to 2wd or 4wd it does not affect the engine as long as it has sufficient power.