In my case, I've changed my iswara headlamp to the aftermarket crystal lamp and i use back my old lamp H4 socket to replace the crystal lamp H7 socket. Why? Because H7 bulb cost RM 60 each while the H4 cost half of the H7.
I bet y'all know the MUT, a bulky hand device that so-called tuners connected via a connector to ECU and was used to 'tune' engines (with stock standard ECUs, especially local cars).