There are other patches too, things you have to do by hand. To get the XP manifest to work you'll need to patch comtrl.pas fo example. Then there are also updates for the help, interbase Express, interbase driver, quickreport, informix, etc.
Good luck! Btw, the runtime patch 3 is not enough to my knowledge (unless it's included in D6_upd2_ent.exe). To be on the save side I would advice to install RTL_2 too.