I had the same question and I had a Dart 3. It depends on your weight and what types of trails you will be riding most. I am 265 lbs. which made it more of a need. If you have it tuned as tight as it will go, and you are still bottoming out quite a bit, then yes, upgrade. You need to remember though, as I had to learn, you want at least some sag and some softness, otherwise you would just be as well off to get a rigid. One last bit, on "another hand", my LBS guy usually says to just ride and only upgrade when something wears out (get your money’s worth out of it) except for two components: fork and rear deraileur. If the Dart1 is not bottoming out too much, then maybe stick with it, but a better fork if you have the money, is never a bad investment.