Be clear , I quite didnt get what you conveyed. "to drive 4/8 Ω@ 300W " Amp should be 300W driving 4/8 ohm speaker? Define the OHM in a proper manner 4 and 8 ohms are different loads altogether!
Could you mention speaker brand and model and the budget you have allocated for the amplifier? Do you have any requirement like Stereo or multichannel , Pre and Power amps etc etc.
A real 300 watts rms Stereo power amp rated at 8Ω will cost upwards of Rs 250000 !!! And a suitable speaker supporting that kind of power effortlessly will cost even more!!!
So please tell me what kind of speakers do you intend to drive. The brand and model.