Maybe you won't need anything. But many people have to fiddle with the bike to make it fit. Top tube length, and thus the reach to the bars, which is your main area of concern, can only be compensated for to a limited extent. But Dahon size the bikes for 'most' people. Outside of that, if you don't fit it, spare parts can help, but only to a limited degree. In addition to a new stem, mountain bike 'riser' bars can be fitted cheaply to add back-sweep, bringing the bars closer. In the US I think there's a trend for older 'cruiser' or 'sit up and beg' style bars to be available, less so in the UK these days. If your legs fit the bike, getting the reach to fit is usually just a case of spending a little more cash.