For dholki sound visit a exhaust repair vala , most probably catalyst is removed datz da cause , for knocking use mix of hi octane and normal petrol or just hioctane if u can afford
Dat grr grr sound is abs kicking in , if its kicking in to early and the car doesnt stop , get ur breaks service done , check break leathers if they are genuine or nt , also check ur tyres , tyres having poor grip also causes this