@varun - Finally cracked the ECU signal. Compared all Suzuki manuals and reached conclusion Brown wire is ECM signal for tacho. Searched speedo unit coupler for brown wire and oyla only one brown wire. Dared to connect it and it worked. Needle went all the way upto redline (most installs showed unly 4k at redlining because of half split distributor signal in Wagon R and Estilo)