An overview of our programme to search for rare shape-phase transition in heavy nuclei and the Giant Quadrupole Resonance (GQR) based on excited states will be presented. The presentation will include new experimental data, instrumental details and theoretical calculations. The measurements have been carried out using large array of NaI(Tl) detectors and more recently a large LaBr3:Ce detector for several heavy nuclei, namely, 188Os, 192Pt and 196Hg. The angular momentum gating have been carried out using a sum-spin spectrometer in soccer-ball configuration covering nearly 4-pi solid angle. Details of the 4-pi spin spectrometer including measurements and simulations will be presented. The very recent results of our testingss and simulations for LaBr3:Ce detectors used in our measurements will also be presented. The talk will endeavour to provide a comparative study of our programme with global efforts, the general paradigms and emerging trends.