Original: By comparison , the 180 Â flat-6 boxer engine is only moderately wider than the 120 Â V6 , and unlike the V6 is a fully-balanced configuration with no vibration problems , so it is more commonly used in aircraft and in sports\/luxury cars where space is not a constraint and smoothness is important .
Simplified: The flat-6 boxer engine ( 180 Â ) is only slightly wider than the 120 Â V6 , and it is a fully-balanced .