I would recommend AGS! I have recently installed Daewoo maintenance free battery in my Vitz 2015 model 1000 cc car, almost 02-03 months ago, but not feeling satisfied now. I think, battery ney kisi b din, kisi b waqt jawab dey jana hai, feeling massive drop in its performance in just 03 months.
Regarding capacity, I would suggest to only go for that battery capacity, which is recommnended for your car; neither less, nor more! If 20Hr capacity for your ride is 45Ah, you should only go for that rating, as it would best suit your ride.