To grade the places suggested in terms of brands, price range and priciness factor (all from memory so there will be some slippage and lapses in absolute accuracy, especially of brands):
The Shop, DN Nagar: Denon, Cambridge Audio, Polk, some Rotels, etc, a number of speaker brands like Canton. I found them pricier than others.
Alliance4, DN Nagar: Mordaunt Short, Mission, Marantz, etc. Moderate pricing.
Viola, DN Nagar: Denon, Marantz, Polk, Canton, etc. Best price I saw.
Boom-a-rang, Juhu, CST, Borivali: Juhu is best stocked, CST also OK, Borivali is not well stocked. Monitor Audio, Accuphase, Yamaha high end, Usher, (my fav) Morel, Quad, Chord cables, etc. Boom-a-rang is a much higher end shop compared to above.
Lakozy: I remember seeing lots of PSBs. And Supra cables.can't recall other brands.
Audio Vision CST is also very high end. You can check their website for their brands.I remember they stock B&Ws and they are Indian distributors for Audio Research.
And then there are JBL at Palladium in Phoenix Mills Lower Parel, ProFX at Atria Mall Worli.
You should give urself 2 days to pay a proper visit, bring along your fav CDs.
All the best. It's great fun to hunt for stuff.
Joshua