yeah man you can do exactly that. i can sell you a d2s ballast with universal connectors on one end. the key is to piggyback the ballast off the headlight leads that go to the OEM ballast. Saves 100$'s over oem.
you'll need to poke around a bit with the ballast to get the right wires.
Hot: 2001 Estoril M Roadster
ZCP 19's, ZHP knob, JL 8W3
Cold: 2002 TiAg M3 6mt
ZCP 19's supersports, ZHP knob, UUC short shift GROM, OEM 18's w310's,
http://absolutehid.ca hid kit