Hi Prasad,
If there is a problem it can be rectified but u will have to pay parts/labour and sometimes blatant overcharge!!!!
Also some of the distributors here do not conduct even a paid service/repair on stuff not purchased from them.
Am not sure of onkyo but the warranty offered on most AVRs is 1 year so if the price difference is vast u could consider grey.
I personally buy stuff like cell phones, DVD players etc from grey but have purchased the Audio gear through the country distributor for peace of mind!
Regards