HRs and any DE Rev-Up registered after 22 March 2006 (so most of them) will see their road tax rise by £15. DEs, or anything registered before 23 March 2006, will go up by £10. See the table about a third of the way down here: https://www.autoexpress.co.uk/car-news/consumer-news/88361/tax-disc-changes-everything-you-need-to-know-about-uk-road-tax .
So DEs and very early Rev-Ups will be £325, and most Rev-Ups and HRs will be £570. That's quite good as I was expecting my HR's road tax to go up by £20 this year rather than £15, so happy days.
As has been rightly pointed out above, the difference is a few tanks of fuel. And, in addition, you'll pay far more than one year's difference to make up the performance difference.
Having owned both: the DE (Rev-Up) engine is more characterful; the HR engine is the stronger and the stronger performer.