Best would be buying a set wipac quadoptics or a pair of cibie bowls and fit philips xtreme bulbs 55w (not more or it wont be road legal)
A rewire from relay to lamps is reccomendable becuase these models, although already fitted with a relay switch as standard, their wiring is still not so good. Still have to give an in-depth gander at this but after halogen conversions the wiring is too hot and eats too many rocker switches, it shouldnt take all this current through the rocker switch..
Wiring the lamps to a new relay with signal feeded by the original relay headlamp feed sounds like a good solution