Tonally, the Radius speakers would match the HK amp. If it's an option, I'd go for the R180s. The R90s only go down to 80HZ as their lowest frequency and that may well be the -3db point. Thus, to be on the safe side, you'd need to set the crossover to 100HZ. With the R180s, which go down to 60HZ, you'd be fine to set the crossover at the standard 80HZ.
The non HD version should be much cheaper than the HD version (by at least half) and the general concensus is that the HD version is not worth the extra.
dont forget, the centre should be from the same range as the L&R to ensure tonall matching across the front soundstage.