Delta is NOT known for making quality lighting products (their claim to fame was the headlight system for the Yugo).
The Phillips Xtreme Power bulb and a supplemental wiring harness would help. But not as much as returning the Deltas and getting some Cibies, Marchals, or Hellas.
Fatboy bulbs from IPF are for offroad only. They move the filament in a way that renders them illegal for on-road use.
And we all know by now that putting a rebased HID capsule into a housing that was designed for halogen is illegal, unsafe, and just plain obnoxious to other drivers.