Hi,
Audio is subjective, and while many speaker-amplifier combinations can be recommended, the best way to find out a suitable and matching amplifier for your speakers is to try it out yourself. Don't be too bothered about integrated or pre-power. What is more important is the sound, and a good amplifier from both the camps will deliver.
So how do you go about identifying a good matching amplifier for your speakers?
(1) You are based in Mumbai - which has quite a few audio stores. Please check with these places and see if you can take your speakers to these places for an audition with their amplifiers. Some may be willing to let you try these at home if your commitment to buying is strong (in case you like the sound)
(2) If you are open to experimenting, you can buy amplifiers used, and try them in your system. If you do not like the sound, sell it. Yes, you may make a small loss in this transaction, but still better than investing big money in the wrong amplifier upfront.
(3) Seek out FMs in your location who have similar speakers (Focal) and try and listen to their setup. Most FMs here are open to letting others come over and listen to their setup. This will help you understand what are the preferred combinations and also what is your taste
As I mentioned before, there is no substitute to hearing on your own since each of us have different preferences, and hence my recommendation may not be what suits you. Like food, you will need to discover your own preferences - otherwise you will be disappointed. 'Pasta' may sound wonderful to you if I write eloquently about it, but you will never know whether you like or not it till you taste it!
Best,
APK