If you are using it for the street I would get a KTM LC4 based engine or the new Husky 610SM. The maintenance is very similar to your R1 which consists of pretty much nothing comared to the 450's. You can also go with the DRZ which is pretty street friendly but lacking the power of the 600's and just as heavy. I owned a Duke II and a 625. I would def. go for the 625 over the Duke, it comes set up with everything and has all the updates.