Pirelli DR3 or Metzeler sport tech M7RR?

I don't think you can go wrong with either one. I have not used the DR3 only the DR2, and it's a good tire. The M7RR is also great, and pretty cheap.

I think you might get some more mileage from the DR3 if it's anything like the DR2.

I have DR3 now and am happy with it. needs some km warming up, but then its great. km possible are not so much, after 3000 km it is at 2mm, which is our legal limit in Austria.
i am thinking of using it still at 2 trackdays mid august. but to be on the safe side when it gets really hot (in hungary on pannoniaring) i ordered Supercorsa SP as backup.
For roaduse i already ordered a new pair of DR3.

Actually it is nearly the same tire as the Metzeler M7RR. Metzeler belongs to Pirelli and i am not sure, but i think., they are even made in the same factory.
In all tests i have read in the last time DR3 and M7RR have nearly the same ratings in different categories.

Best tire i used on my former HS821 was the Michelin Pilot Power 3, but it seems it does not match with Hyperstrada TC because TC interventes much too early.
Seems the extent of the michelin from front to rear tire is different to the Pirelli ones so that TC means that rear tire slips when it still has lot of grip.