1. 3 cylinder is naturally imbalance, it will vibrate
2. 3 cylinder engine mounting ranges from cheap to expensive, cheap one like perodua, interior will feel the vibration
expensive one like ford fiesta will make sure the vibration doesn't reach the interior/driver
so you're gonna pay more when the mounting is worn

and no.3 is what i found out recently, not just 1 case but many case already
they all will say my engine vibrate...like "boss, your engine vibrate oh"
apparently many(including people working in the car industry) do not know that 3 cylinder engine will vibrate
and they take u like some stupid people and say your engine vibrate to lower your resale value
so if u own a 3 cylinder engine car, chances of u being low balled when u sell is very high