I'd leave that bike alone until i got the $1700 bike, then put some slicks/rigid/rack/fenders on that bike and make it a commuter. I think the dart would be only marginally better than the spinner. My friend has a spinner, and I have a Judy TT which i've heard is the older model of the Dart, and ours are not that much different. They both can handle curbs, though, if your spinner can't do curbs there might be something wrong with it.