The holes in the rotors are a different size between the two, there is a way to use one rotor on the other but I forget which way that goes.
As for modifying DRW to make them SRW width, it's generally considered unsafe. The SRW hubs have material all the way around the wheel mounting surface, the DRW hubs have roughly half that (they are kind of a clover leaf pattern) where you would want the wheel to mount.
There have been people that have done all kinds of modifications to DRW hubs, turning off the OEM wheel mounting surface, welding pieces to fill in the gaps on the DRW hubs, welding a ring over the DRW inner most 8 bolt pattern (to make a new WMS) etc. No matter how much material is added, welding, machining etc. you'll always end up with a non heat treated, weld heat affected part that won't be as stout as a stock SRW hub.