for 15k, i would suggest you the following setup-
Pioneer HU (anyone with USB & 2 pre-outs) - Rs. 7k
Front component speakers (JBL/Kicker/Auditor) - Rs. 5-6k
2 channel Amp for the front comps - Rs. 3k
I have not included the cost of wiring & labour. Also, i am assuming that you will be the one driving, so front speakers should be better than rear. so you can sacrifice rear co-axials for the moment & get better front comps. also, front comps wont work without an amp, so please do buy an amp for the comps.
Also, i would recommend Auditor & Kicker at this price range over Boston.