I've used them, they're an exceptionally good sounding tweeter ... when applied correctly. As a replacement in the Ekta Grande linked it would work well, the R-1 likes a 3000hz or higher crossover point, that speaker crosses at 3500. They are also very fast, the Scan 12m is one of the fastest mids around, so they should integrate nicely.
Of course you'll have to start from scratch on the tweeter x-over. Try starting with a 3rd order electrical and either leave the rising response alone or tailor a notch to level it out.