You can order the part from and dealers mate. Use the search feature for revision D and there's plenty of old threads with the part number on if needed. You can get them to got it or do like I did and use a local garage to fit it for about £30. Alternatively you can fit it yourself if you have the right tools. Use the search again and you should find a few guides on how to fit it.
I would suspect you'll be fine with the remap but there is always that slight risk. If your like me you just need somebody to say it'll all be ok before you go ahead. The map will basically bring out any weak points. For example if you clutch has say, 2000 miles worth of life left then the map will reduce that to say 1000.
For that reason I bought the bluefin device. Partly because its slightly less potent than say the revo but also because I could revert back to stock if the clutch started to slip.
It'll all be fine anyway so just go get it bought