Sports suspension gives a firmer ride. The Sport models also come with bigger wheels and lower profile tyres than the standard 235/65R17s which is also an off-road negative in terms of ride and puncture resistance. But if you are only taking about "driving on dirt roads very sensibly", the Sport package won't be a major compromise but it will still be a compromise. It all depends on how often you'll be driving away from sealed roads and the distances you plan to cover on these "dirt" roads.