Need help on Dzire ICE upgradation

Hi,

Recently got my Dzire Zdi. am in love with it completely, except one thing i.e, ICE. Though I am tight on budget, I would like to change my speakers only and not the HU.coz i like the integrated look. 

1) Will just upgrading the rear speakers with coaxial Pioneer TS-6974R improve the SQ a little bit???

2200 INR

2) Dealer is urging me to go for JBL components for the rear , promising me a SQ 5-6 times better than the stock, but as far as i know , components are only installed in frnt. Also is the cost right???

JBL 608 series - 3800 INR...

I dont intend to change the HU, so i think even if i stretch my budget i cant go for Amp.???

Upgrading the rear speakers to pioneer or JBL 6*9 coaxials(mounted on the rear parcel tray) will definitely increase the sound quality.You will fell some extra bass when compared to the OEM speakers.Also check JBL GT6-S699 and JBL GTO 949.