Hi Partho,
1. Bass Treble, Coimbatore has sold a Marantz PM 15S1 to one of the forum members by the name "Dali" in the last few months at 63K. Another member member Sidharth_Trehan also has the same amp, I think. They know about the seller in Coimbatore, I guess. Find out about bill and warranty and whether that is an authorized Marantz dealer. You can send PMs to the members to find out more. Look at page 5 of the following thread:
http://www.hifivision.com/speakers/2331-dali-ikon2-speakers-5.html
(if you can, please read the whole thread).
2. SKS Traders Kolkata had only a Diva A 90 last time (a week ago) I enquired. That is priced at 89K, so no discount. They sold their last A 70 piece at 50K a month ago, again at no discount. In Mumbai and other places, there were discounts going on before the older models gave way to the newer FMJ amps. I guess in Kolkata it is still the seller's market.
3. The Quad 909 is a power amp and would drive your speakers and a lot more effortlessly, however, you need a pre-amp with that. This amp is in a different class altogether from other amps so far discussed in this thread.
4. Although I have not heard any of the newer FMJ amps from Arcam, I would imagine they are all very clean sounding. The FMJ A 28 at about 70K would definitely drive your speakers well, but I do not know about the A 18. Forum member "particleman" owns the A 28, and you can find from him more. He has coupled this amp with a pair of MA speakers.
5. The word that is going around is that the newer Nad c355bee amp is pricier and inferior than the older 352 amp which was very very good for the money. See if you can find an older one.
6. The Nad and the Arcam sounds are very different. The Arcam produces a very clean and musical sound (at least to me) with good dynamic range and the Nad is not clean sounding, the sound is colored a bit, but it is 'musical' and the available dynamic range is good for the price with a huge soundstage (the older Nads that is, have not heard the newer ones). You have to hear both with your speakers to see which you like.
7. At the end, let me say, since you have already the speakers, you should now audition all the amps in your shorlist with your speakers and decide. Chennai, unlike Kolkata, has many stores and many brands are readily available there. There are members from Chennai like Venkat and Vortex who can guide you about the stores.