Have you seen the S&V review on the X4200W? In that test, it measured about 94W, 5 channel driven, at 0.1% THD and about 77W, 7 channel driven, also at 0.1% THD. All into 8 ohms obviously.
The X4300H appears to have a slightly larger power supply so expect it to do a little over 100W 5 channel and 85W 7 channel.